General Articles Right Arrow About Right Arrow Catfish FAQ • Article © Julian Dignall, uploaded August 04, 2010

  1. While cleaning aquarium, one of the catfish's fin rays poked me in the finger. Now the site is purple, swollen and sore. Are catfish poisonous?
  2. What is the largest catfish in the world?
  3. I have a raphael catfish with a distended belly. It looks pregnant! What is going on?
  4. How long, on average, do Corydoras live?
  5. Why do Corys lose their barbels?
  6. What do catfish eat?
  7. What does SL, TL and FL mean?
  8. How do I tell if I have a male or female bristlenose (Ancistrus spp.)?
  9. What is a general description of a catfish?
  10. How long can catfish live out of water?
  11. What would be a good catfish for beginners?
  12. Whatever happened to the blue-eyed pleco?
  13. How do you tell the sex of a common pleco?
  14. Do catfish shed their skin?
  15. Why do catfish have whiskers?
  16. I have sand instead of gravel. Would I still be able to get a pleco? I'm not sure if that would harm it in any way. Maybe affect his breathing or anything like that?
  17. What is it called when people swim underwater and catch catfish from under rocks using only their hands?
  18. What is the best catfish or pleco for taking care of algae in my tank.
  19. How long do the larger 10-20 inch plecos live in captivity?
  20. Do catfish menstruate?
  21. My red tail catfish (or, generally, large catfish) has stopped eating several weeks, no sign of disease, active, acts hungry but spits out whatever it occasionally tastes. What is wrong?
  22. Could anybody tell me what kind of catfish I have?
  23. What is the function of an adipose fin in (cat)fishes?
  24. Can catfishes (especially corys) breathe atmospheric air? If they leave the water in search for other waters, how do they breathe? Do catfish have lungs?
  25. Which pleco is best for a planted tank?
  26. What are the best books and websites to teach me about catfishes?
  27. What does CF stand for?
  28. Could someone please explain the basics of taxonomy?
  29. What are these cheek "horns" on pleco? I have a pleco stuck in net, what should I do?
  30. I want to go collecting abroad. Should I hire a company and take a "tour" or just go it alone?
  31. How can you tell if a catfish is a boy or a girl?
  32. Could anyone tell me if adding salt to my aquarium will be harmful for my plecos?
  33. I want to breed Zebra Plecos and I have so many questions? Where should I start?
  34. What are the "L" Numbers I see everywhere? What about "LDA" numbers?
  35. Is there such thing as school (or shoal) of catfish?
  36. Is a catfish an amphibian? Because of its smooth skin and ability to breath air?
  37. Do all catfish have whiskers (barbels)?
  38. Is catfish skin edible? If not, why?
  39. Do catfish have lungs? If they leave the water in
  40. How many breeds (or species) of catfish are there?
  41. How do I sex my Synodontis?
  42. What is the correct plural for Corydoras? Corys or Cories?
  43. Where does the name catfish come from?
  44. As a pleco gets bigger will they eat smaller fish?
  45. My catfish lost his barbels by getting stuck in a rock. Will he be OK and able to eat properly?
  46. How do catfish hear?
  47. Can catfish see at night, or in the dark?
  48. How do I use the Youtube tags in the forum?
  49. How do I use CLOG tags in the forum?

 

  1. While cleaning aquarium, one of the catfish's fin rays poked me in the finger. Now the site is purple, swollen and sore. Are catfish poisonous?
    Some are, most are not. Most will inflict a painful wound with their rays (not with their whiskers or barbels). Most commonly the dorsal (top) or pectoral (side, behind/below the gill) fins do the damage. Always clean the wound, check for residual pieces of spine and apply antiseptic. Those to worry about are Heteropneustes and Plotosus which have venom glands and will inflict a very painful stab if incorrectly handled. [back to question list]

  2. What is the largest catfish in the world?
    The largest catfish in the world is Silurus glanis, the European wels. See here for more info. You may also be interested in reading In search of the worlds largest catfish for which fish is the largest in each part of the world. [back to question list]

  3. I have a raphael catfish with a distended belly. It looks pregnant! What is going on?
    Technically fish don't actually get pregnant, they get full of eggs and that's called being gravid. If the eggs aren't released then this condition is referred to as eggbound but this isn't documented in these catfish at all. However what is a common worry of new keepers of raphael catfish, is a huge belly. In these cases, the fish has just eaten a lot (they do that) and you should maybe think about feeding your fish a little less. They will only gorge like this if hungry, you can't rely on them always cleaning up leftover food. Don't feed your aquarium for a few days and try feeding a little at night when this fish is most active. [back to question list]

  4. How long, on average, do Corydoras live?
    In the aquarium most species should live at least six years, larger species tend to live longer. [back to question list]

  5. Why do Corys lose their barbels?
    There are several reasons why Corys lose their barbels, the first being the type of substrate they are kept on. Sharp sand or gritty gravel particles are very abrasive and can cause inflammation to delicate barbels. The substrate should be smooth grained and small, for example well-washed river sand or fine silica gravel, these have grains that are rounded like beach pebbles.

    The next area for consideration is the depth of the substrate, which should be no deeper than the depth that the Corys kept over it can penetrate, enabling them to reach the base of the aquarium. This will ensure all food particles can be found and eaten.

    Finally, poor water quality, such as a very low pH (below pH 5)and high ammonia levels will, very quickly, cause barbel erosion although this is most commonly experienced during the import process.

    Once barbels have become damaged they are susceptible to secondary bacterial infection that can develop into serious mouth fungus, which is usually fatal. Quite often the first signs that something is not right is when the barbels start to loose their length and this is the time to check the cause or causes not when they have been reduced to little bumps at the side of the mouth. Very rarely will severely worn barbels regenerate fully. [back to question list]

  6. What do catfish eat?
    Everything! This really depends on the species (and there are more than 2000). You need to be more specific - identify your catfish first (the what is my catfish forum is a good idea) and then look it up to find out its requirements. [back to question list]

  7. What does SL, TL and FL mean?
    SL (Standard Length) refers to the distance from the tip of the snout to the base of the caudal fin (tail).

    FL (Fork Length) refers to the distance between the tip of the snout and the fork in the tail.

    TL (Total Length) is the total length of the fish, from snout to the tip of the tail. [back to question list]

  8. How do I tell if I have a male or female bristlenose (Ancistrus spp.)?
    Some cases are obvious: Males have big head tentacles and females don't, but it's not always so clear-cut. First of all, some females do get head tentacles - although not to the same extent as a male from the same species - which can make it hard to determine if the fish is a young male or older female. It can be useful to be able to determine if a young fish is male or female, before the head tentacles have grown, so here are a few pointers. If you have multiple reasons that all point in the same direction, you have more confidence that it is either male or female.

    (1) Head tentacles up into the face.
    Males will have head tentacles above the edge of the snout.

    (2) Forked head tentacles.
    Males of many species will have forked head tentacles, females don't.

    (3) Ridge in the face.
    On males, the snout has a ridge going from the tip of the snout up towards the middle between the eyes.

    (4) Body shape.
    Another part of the puzzle is the shape of the body - females tend to be wider around the tummy area than the. Males are continually narrowing from the head back, females are a little wider around halfway between the pectoral (back of the head) and ventral fins (back of the tummy area). This is of course most evident if they are heavy with eggs, but even juveniles will show the difference in body shape.

    (5) Slimy snout or not.
    If you catch the fish and "feel" along the snout, a male is smooth and a little bit slimy, female would be dry [as in not slimy] and "rough", like fine sandpaper.

    (6) Relative size.
    In a group of siblings of the same age, the bigger ones will most likely be males; smaller ones are more likely to be female. This is not a very good indication, but if you pick a bunch of juvenile fish to start a colony, it's good advice to pick a few of the bigger ones and a few of the smaller ones, to give a better chance of having at least some mix. [Of course, for breeding purposes, you want to have fish that are unrelated to be the parents. However, that's a different subject! [back to question list]

  9. What is a general description of a catfish?
    In terms of external features, catfish have no scales (but some have armour plates) and most have pairs of whisker like barbles stemming from around their mouth - in many species the mouth is a sucker like adaptation. Most are nocturnal and there are a well over two thousand species that can be found all over the world. [back to question list]

  10. How long can catfish live out of water?
    This depends on the species of catfish. Most will live a few hours if kept wet or are lying on something damp.

    Some catfishes do have the ability to survive for quite a while out of the water, and this is largely due to their ability to utilize atmospheric oxygen. They may do so in two ways:

    (1) use specially modified organs or

    (2) absorb atmospheric oxygen through their gut.

    The first strategy is only seen in clariids (the well-known walking catfishes). In clariids, a special organ known as the suprabranchial organ is formed from modifications of parts of the gill arches. Looking somewhat like a bunch of grapes, the suprabranchial organ is richly supplied with blood vessels and functions pretty much in the same way as lungs do.

    The second strategy is seen in loricariids (plecos) and callichthyids (Corydoras and their relatives), and is an adaptation to surviving in oxygen-poor waters rather than a mechanism to enable them to climb out and search for other water bodies. [back to question list]

  11. What would be a good catfish for beginners?
    There are many different forms of catfish, and this list is just a brief list of some of the more commonly encountered and easy to keep species.

    For tanks that are less than 100cm/200 liter (40"/50 gal):
    Captive bred bristlenoses Ancistrus cf.cirrhosus and "false" Ancistrus sp(L144)
    Corydoras spp
    Panaque maccus

    For a bigger tank, the choice is wider:
    Captive bred Sturisoma festivum
    Common plecs (Pterygoplichthys pardalis, Sailfin-plec P. gibbiceps and P. joselimaianus)
    Riverine Synodontis like S. nigrita, S. eupterus, S. ocellifer and S. robbianus.
    Captive bred Rift lake Synodontis, e.g. S. lucipinnis and any variety of captive-bred S. multipunctatus.

    Note: Synodontis species are well adapted to be kept together with many cichlid species, which is more than can be said for most other catfish species.

    Dianema spp. and Brochis spp. These are like "larger Corydoras".
    Megalechis thoracata, Hoplosternum spp.
    Mystus tengara, Pseudomystus siamensis, Pimelodus pictus, Agamyxis pectinifrons, Amblydoras nauticus and Platydoras armatulus.

    Some species, such as Pimelodus pictus and Corydoras species are best kept in a group. Please refer to the respective links. [back to question list]

  12. Whatever happened to the blue-eyed pleco?
    The blue-eyed pleco, Panaque cochliodon , was misidentified in the hobby for years with its close relative P. suttonorum. The blue-eyed pleco was collected for the aquarium trade from the middle Rio Magdalena in Colombia. This section of the river, in fact most of the river, is now heavily polluted and populations of this fish have fallen to the point that commercial collection is no longer profitable. Populations of the blue-eye pleco still exist in tribuatries of the lower Magdalena, but this area is under the control of various paramilitary narcotics trafficking cartels making collection all but impossible. Rare specimens show up from time to time, but it will be some time, if ever, we again see this fish appear in any numbers in the aquarium trade. [back to question list]

  13. How do you tell the sex of a common pleco?
    Look underneath at the genital papillae, there are quite a few example pictures in the Cat-eLog. You can find them by searching the site for the word "papillae". [back to question list]

  14. Do catfish shed their skin?
    Most catfishes don't shed their skin, but a few that have heavily keratinized skin do (keratin is a waterproof protein that makes up a large part of your skin and hair). These include the South American banjo catfishes and some Asian hillstream catfishes. The skin peels off in chunks as it is being shed and the fish is none the worse for wear (except that tankmates may sometimes try to eat the dead skin off the fish). This shedding process is the natural result of the keratin deposition and it happens to humans on a daily basis as well (your skin is shed as tiny flakes which one does not usually notice). [back to question list]

  15. Why do catfish have whiskers?
    Because they do not have razors! Just kidding. Catfish whiskers, or barbels, are sensory organs that help catfishes find food. The barbels have a high concentration of tastebuds that assist catfishes to locate food in different ways. Some catfishes, like corys, have short barbels that help them sense food items just under the substrate. Many large predatory catfishes have very long barbels that widen or amplify their ability to to detect prey in often murky or dark waters. [back to question list]

  16. I have sand instead of gravel. Would I still be able to get a pleco? I'm not sure if that would harm it in any way. Maybe affect his breathing or anything like that?
    Sand as a substrate is fine with all plecos. About the only trouble is with large plecos moving the sand around and it then finding its way into the filter. Some fish in the Loricarinae (whiptail catfish) pleco subfamily even require sand to feel happy in the tank - several actually need to bury in it. [back to question list]

  17. What is it called when people swim underwater and catch catfish from under rocks using only their hands?
    In North America this is called Noodling. Search the web for catfish noodling and you'll get a whole host of crazy folks telling their noodling tales. [back to question list]

  18. What is the best catfish or pleco for taking care of algae in my tank.
    Plecos are catfish, some eat algae and some do not. The best algae eater depends on the size of your tank. For small tanks (24"/60cm or less) try six Otocinclus, for larger tanks (48"/120cm or larger and at least 15"/38cm wide) try a Hypostomus or Pterygoplichthys. For tank sizes in between, try one Ancistrus for every 18"/45cm of tank length. If you are overfeeding, these species will usually eat that food in preference to algae and indeed the algae will tend to grow faster. Once these species eat the algae you'll need to feed them other foods - see the Shane's World article on feeding plecos. All said, you're better off trying to find out why you've got an algae problem than react to one by adding fish. [back to question list]

  19. How long do the larger 10-20 inch plecos live in captivity?
    At least 10 years, a lot longer (past 25) if kept well. [back to question list]

  20. Do catfish menstruate?
    The notion that a catfish could menstruate is preposterous and flys in the face of basic biology. Only primates (humans, apes, and monkeys) are set up biologically for a reproduction strategy that involves menstruation. Primate reproductive strategy runs from month to month and involves internal fertilization. That means that the male actually releases sperm into the female's body. If a female primate's eggs do not become fertilized within a specific time period, she sheds the blood and mucosal tissue from the uterus and the cycle begins again.

    Catfishes do not even have a uterus! In most catfish species, the female becomes gravid (i.e. fills up with eggs) on an annual cycle that, especially in the tropics, is associated with the onset of the rainy season. Most catfish females then find a mate and expel their eggs (there can be a few dozen to thousands of eggs depending on the species). The male then swims over the eggs and releases sperm to fertilize them. There are a number of very interesting exceptions to this generalization, but this is the norm for most families of catfishes.

    So to provide a simple answer, only primates utilize menstruation as a reproductive strategy and cold blooded fishes do not even have the necessary organs for menstruation. [back to question list]

  21. My red tail catfish (or, generally, large catfish) has stopped eating several weeks, no sign of disease, active, acts hungry but spits out whatever it occasionally tastes. What is wrong?
    These fish tend to go on a hunger strike if water conditions aren't good. This also assumes they are in an appropriate sized tank. Four times the total length of the fish and one and a half size of the fish as width as a bare minimum guide for the purposes of this answer. Larger fish will produce "spikes" of waste that can quite easily overpower the filter and rapidly affect the quality of their surroundings.

    Check for ammonia/nitrite as often as you can periodically, say every 4-6 hours for a 36 hour period. Check temperature similarly. Consider additional filtration. If all check out perfectly, move the fish to larger, mature, aquarium and repeat testing. Do not feed for first week of move. [back to question list]

  22. Could anybody tell me what kind of catfish I have?
    YES! There are many who can help, you need to post a picture of your fish in the what is my catfish forum once you've checked it's not in the commonly asked about species. You'll most likely have it identified in a matter of hours but please be patient and remember that the better the request for ID title and the more information given as well as a good picture or two will speed replies. Even if you don't have a picture, a good textual description will at least help us point you in the right direction. [back to question list]

  23. What is the function of an adipose fin in (cat)fishes?
    No one is really sure what the exact function of an adipose fin. The two most plausible theories have to do with swimming.

    (1) The adipose fin functions to control vortices enveloping the caudal fin during swimming (these vortices would reduce swimming efficiency).

    (2) adipose fins are a passive precaudal sensor of turbulent flow (again, this has to do with swimming efficiency).

    Experiments have been performed on young salmonids that show that the amplitude of movement of the caudal fin increases significantly in individuals of a certain size when the adipose fin is removed. However, the jury is still out as to the exact function of the adipose fin. [back to question list]

  24. Can catfishes (especially corys) breathe atmospheric air? If they leave the water in search for other waters, how do they breathe? Do catfish have lungs?
    Yes, some catfish, particularly Corydoras and most Loricariidae (plecos) are able to "gulp" air and use the oxygen in the air to help survive under low-oxygen periods. They will do this from time to time under normal conditions, only if more regular, a few times and hour, should you check filter outlet / current, oxygen levels and temperature.

    Catfishes do not have lungs. Lungs are actually modified swim bladders, and while catfishes do have swim bladders, but they do not use their swim bladders for gaseous exchange the way we use our lungs. [back to question list]

  25. Which pleco is best for a planted tank?
    The problem with loricariids (plecos) in a planted tank is that this is not the correct environment for the majority of species. Contrary to popular belief, the suckermouth was not developed to scrape algae, but to hold onto rocks in medium to strong current. These catfish need an environment with a lot of current and high oxygen levels. This is the opposite of what we are trying to achieve in most plant tanks where we want to conserve CO2 for the plants. A tall tank is also less suitable for these fish because we want a large surface area to water volume ratio to increase O2 exchange. Taller tanks have a small surface area to water volume ratio and thus gas exchange at the surface is inadequate without serious turbulence. While this rules out many plecos, it still leaves you with some interesting options.

    (1) Ancistrus species (bristlenose plecos) stay small enough for your tank and will spawn if provided with a suitable hollow log. They will not bother other fish and most species will not damage plants. There are a number of species with an overall black body and white spots that are very attractive. I would suggest one male and one female. The only disadvantage is that Ancistrus are messy (produce a lot of waste) which is not always best in a small planted tank.

    (2) Otocinclus, Parotocinclus or Hypoptopoma species. These fishes all stay small and are plant friendly. Provided the tankmates are only small tetras you may even be lucky enough to spawn one of these species. A group of six of any of these species would be great and still allow room for some small tetras or dwarf cichlids.

    (3) Sturisoma or Farlowella. Sturisoma make a striking display and are very attractive fish. Since they grow rather large just a pair is recommended. Farlowella are bizarre in appearance and the tank could hold three or four. Both species will spawn in a planted tank on the glass near the filter outlet. Whichever you choose, realize that these fish will need additional fresh greens in their diet. Most pet stores carry a clip with a suction cup attached that can be placed on the glass inside the tank. Feed cucumber, zucchini, squash, and spinach on a rotating basis with a meaty meal, brine shrimp or bloodworms, twice per week. For all of the above fish, you should shoot for neutral to slightly acidic water with a low overall hardness. This is also an ideal chemistry for most aquatic plants. [back to question list]

  26. What are the best books and websites to teach me about catfishes?
    For the best website, look no further than planetcatfish.com! Check out our reviews of most catfish books available here. [back to question list]

  27. What does CF stand for?
    The abbreviation cf. stands for "confer." It is used to denote a species you believe to be the same as a described species, but need more information to confirm. Thus Panaque cf. maccus means that the fish is most likely P. maccus, but the author needs to confirm the identity. [back to question list]

  28. Could someone please explain the basics of taxonomy?
    It is quite understandable that many, even advanced, aquarists are unfamiliar with basic taxonomic concepts. Every hobby-oriented aquarium book that I am aware of lists all the fish by their scientific name, but they rarely include even a small chapter on how classification works! As hobbyists become more specialized, they begin to see that the current taxonomic distinctions in scientific literature do not always correspond to what they observe in their aquarium. Here is a very basic explanation of the system that we currently use.

    When a scientist comes across a new fish they collect a number of samples and preserve them. One of these samples is picked to be the type specimen of the species and is referred to as the holotype. This holotype is then compared to other closely related fishes that have been described. If their are enough differences between the "new" species and those already described, a description of the new species is written up and published in a journal. Once published, the "new" fish is now considered described.

    Now the problems associated with this system! First of all, not everyone agrees on exactly what are enough differences to qualify a "new" fish as a distinct species. Those people that believe that even slight differences are enough are referred to as "splitters" while those that want to see more differences are "lumpers". The second big problem has to do with the entire concept of a holotype. Why should an entire species be held to the characteristics of a single individual? What about natural variations? What about differences between the sexes? For example, the original description of "Mystus" armatus used the "anal papilla" as a distinguishing characteristic of the species. The problem is that the "anal papilla" is actually the genital papilla of the male! By a fluke, the original describer only collected males and thus used what are actually sexual characteristics as diagnostic characteristics for the entire species. Granted mistakes this simple are much more rare now, but this is a good example of the problems associated with using a single fish as THE representative of a species.

    However, for all of the problems our system has, it is still the best we have to work with. Hobbyists should explore taxonomy because it offers the aquarist a whole new set of tools to use in their hobby. There are no simple answers, but exploring the relationships of our fish can provide new insights and new possibilities. [back to question list]

  29. What are these cheek "horns" on pleco? I have a pleco stuck in net, what should I do?
    The scientific name for these spines is interopercular odontodes. These evertible spikes can be found to a lesser or greater extent on both sexes of all Loricariids (Plecos) that belong to the tribe ancistrini. This includes common Ancistrus along with many other l-numbered plecos such as Hypancistrus, Baryancistrus and Panaque etc. Have a look at the pictures of Megalancistrus to see a really good example of them. Whether they are an anti-predator mechanism or used in inter pleco territory battles is an open debate, but they also make netting these plecos a difficult business.

    Larger plecos can be caught by a quick one-handed grab but this is a learned skill and usually involves a few painful lessons for the aquarists. Smaller or mid-sized plecos are best given a pipe or cave to hide in, once the pleco takes up residence remove the whole structure with pleco inside. If you do get them stuck in a net, the best idea is to leave pleco and net in the water, preferably with lights off, and come back to it a few hours later. Nine times out of ten the pleco has time to calm down a bit and will free themselves of their own accord. [back to question list]

  30. I want to go collecting abroad. Should I hire a company and take a "tour" or just go it alone?
    There are a few companies, such as Margarita Tours, that offer tropical fish collecting tours in South America. I am able to do most of my international collecting because my job requires me to travel frequently. So basically, you can go it on your own or with a tour company depending on your level of comfort.

    Professional "ecotour" companies that organize collecting trips are much more expensive than if you were to, for example, charter a boat privately but you are paying for much more than a boat. Most companies will also require that you sign a disclaimer against personal injury, death etc. before they accept you on the expedition. Finally you should check details of whether or not the tour company will help you export the fish you have collected, not just out of the first airport, but right through to your final destination. Some airlines will simply not carry live fish on passenger flights.

    You can arrange the permits on your own, but this will require good language ability and time. In most third world countries things do not always happen fast. Some examples, my phone stopped working five weeks ago and the Venezuelan phone company just sent someone yesterday. I went to the Venezuelan DMV to get license plates for my car and was told I could come back in 4 months when the paperwork is processed. For these reasons alone I would suggest a professional tourist company to the average aquarist. I have never used one because I prefer to go it alone, but I have heard great feedback from many people that have gone on the trips to Peru. Search the forum for several long posts on the subject.

    One suggestion I would make is that anyone that is thinking about collecting tropical fish first gain some experience with the equipment. This is best gained by collecting natives. In the USA, take a few trips to collect US natives with your local North American Native Fish Association chapter. These guys and gals will show you the ropes of live collecting techniques from seines, to cast nets, to dip nets, to fish traps. All of the techniques I learned collecting fishes this way have paid off in South America tenfold since you can get right to serious collecting without wrapping yourself up in your own net or wasting your time trying to catch fishes where they do not exist or can easily escape. [back to question list]

  31. How can you tell if a catfish is a boy or a girl?
    Check out the Shane's World article here for an introduction on how to tell. [back to question list]

  32. Could anyone tell me if adding salt to my aquarium will be harmful for my plecos?
    There is no reason to add salt to a freshwater aquarium containing plecos. All plecos come from waters that are low in salt content in nature and do not react well to added salts in the aquarium. [back to question list]

  33. I want to breed Zebra Plecos and I have so many questions? Where should I start?
    One good source of breeding information on Plecos in general is the Reproduction section of Shane's World. In particular these articles will be of interest to the Hypancistrus zebra breeder:

    Spawning Hypancistrus zebra and All About Zebra Plecos

    A more generic look at breeding many types of pleco species can be found here:

    Ancistrinae Internet Lecture and Pleco Breeding Techniques [back to question list]

  34. What are the "L" Numbers I see everywhere? What about "LDA" numbers?
    L- and LDA-numbers and their importance is explained in detail here. [back to question list]

  35. Is there such thing as school (or shoal) of catfish?
    Yes, many catfish school (or shoal) for the same reasons other fish do. Most famous among these are the Corydoras but many catfishes are found in large groups especially those that are found swimming mid-water. [back to question list]

  36. Is a catfish an amphibian? Because of its smooth skin and ability to breath air?
    A catfish is a fish and not an amphibian. The class amphibia consist of three orders comprising roughly 4000 species. Amphibian means "two lives" and refers to the fact that almost all amphibians begin their life in an aquatic form and change to a terrestrial form at adulthood. The osteichthys, or bony fishes (to which catfishes belong), encompasses over 30,000 species. The bony fishes do not undergo the metamorphosis that amphibia do. They also possess a swimbladder organ for buoyancy and their gills are internal and covered by a protective flap called the operculum. The gills of amphibians are always external and unprotected. [back to question list]

  37. Do all catfish have whiskers (barbels)?
    Yes, although the they are highly modified in some species and hardly look as such. Another feature of catfish is that they do not have scales - although some have armour plates that, again in some cases, look like scales. [back to question list]

  38. Is catfish skin edible? If not, why?
    Generally, yes. The exception would be those species that have armoured plates. Many of these are eaten either by roasting whole on hot coals and then eating from underneath with a scooping action or, in the case of smaller armoured catfishes, by adding, usually whole, to soup. [back to question list]

  39. Do catfish have lungs? If they leave the water in
    Catfishes do not have lungs. Lungs are actually modified swim bladders, and catfishes do have swim bladders, but they do not use their swim bladders for gaseous exchange the way we use our lungs.
    Some catfishes do have the ability to survive for quite a while out of the water, and this is largely due to their ability to utilize atmospheric oxygen. They may do so in two ways: (1) use specially modified organs or (2) absorb atmospheric oxygen through their gut. The first strategy is only seen in clariids (the well-known walking catfishes). In clariids, a special organ known as the suprabranchial organ is formed from modifications of parts of the gill arches. Looking somewhat like a bunch of grapes, the suprabranchial organ is richly supplied with blood vessels and functions pretty much in the same way as lungs do. The second strategy is seen in loricariids (plecos) and callichthyids (Corydoras and their relatives), and is an adaptation to surviving in oxygen-poor waters rather than a mechanism to enable them to climb out and search for other water bodies. [back to question list]

  40. How many breeds (or species) of catfish are there?
    A breed can mean something other than being the same meaning as species but, for the purpose of answering this question, lets just talk about how many species there are.

    There are well over 2000 catfish species known to science and counting! In all likelihood there are at least 3000 species of catfish in the world today and some estimates put that at closer to 5000.

    Many are not described to science and do not have formal names yet still find their way into home aquaria. [back to question list]

  41. How do I sex my Synodontis?
    All Synodontis can be sexed by the presence of a genital papilla in the males. In larger cats this is visible as a small protrusion just fore of the anal-fin. With smaller Synodontis you have to pick them up and turn them over. Run your finger down the belly towards the anal fin. If the fish is a male you will see the genital papilla "pop up" as your finger passes over it. Make sure your hands are wet when you pick up the fish so that you do not injure the slime coat. [back to question list]

  42. What is the correct plural for Corydoras? Corys or Cories?
    We have gone with Corys because the root of the word is the Latin and you are shortening it for convenience.

    You say Cory to be short for Corydoras. You would also say ten Corydoras wouldn't you? So, a shortening of that would be ten Corys. Pony, Ponies, Sheep, Sheep, Guppy, Guppies, Deer, Deer - it's the English language that allows for rules to be broken, what falls into common use is what is right and what most often falls into common use is what is easiest - so our house style is Corys. [back to question list]

  43. Where does the name catfish come from?
    The name catfish is in reference to the whisker like barbels found around many species of catfishes mouths. [back to question list]

  44. As a pleco gets bigger will they eat smaller fish?
    Plecos do not hunt other healthy fishes, not even babies; eggs are not safe however. If a pleco is found eating a dead fish, it was either dead or nearly dead by the time the pleco got to it. Many plecos are omnivores and particularly good at finding food around the bottom of the tank. To a hungry pleco a recently deceased fish is a perfectly good meal. [back to question list]

  45. My catfish lost his barbels by getting stuck in a rock. Will he be OK and able to eat properly?
    Most likely, yes the fish will be fine. With many, especially long barbel, species the barbels will grow out again. However, it's a good idea to avoid sharp rocks or gravel in tanks with such catfish, particularly those that like to dig in the gravel. Corydoras spp., for example, are sensitive to sharp gravel and barbel loss can lead to them not growing back out again. Soft smooth sand or fine gravel is best for these fishes. [back to question list]

  46. How do catfish hear?
    Catfishes possess an inner ear that is stimulated by sound waves. Sound is readily propagated through the tissues and fluids of a fish because they have a similar density to water. The inner ear is connected to the swimbladder via the Weberian apparatus to enhance the detection of sound. Think of the swim bladder as a tympanum and the Weberian organ as a humans middle ear bones. Studies have shown that different catfish species have different abilities to hear. Some can hear much better than others. [back to question list]

  47. Can catfish see at night, or in the dark?
    Eyes have light detectors called rods that allow night time vision (nocturnal) and cones that allow vision during the daytime (diurnal). Catfishes have high number of rods and very low numbers of cones. The high number of rods lets catfishes collect more light in their eye and see better. Catfishes have other eye adaptations in addition to rods that increase their night vision. A catfish could still draw in enough light to see when a human would no longer be able to do so. [back to question list]

  48. How do I use the Youtube tags in the forum?
    The youtube tags are "phpBB tags" used to link to videos on YouTube. Inside the tags you want the video ID, which is a set of numnbers and letters all jumbled about, found just after the "v=" when viewing the video on YouTube. Something like this "http://www.youtube.com?v=1bah84-ah&search=related". The video id is 1bah84-ah. To make this video appear in the post would be "[youtube]1bah84-ah[/youtube]". [back to question list]

  49. How do I use CLOG tags in the forum?
    In a forum post (or PM), we have a method to link to the Cat-eLog, called a clog-tag. To use this, just write [clog]species-name[/clog]. For example [clog]Corydoras sterbai[/clog] will show up in the post as Corydoras sterbai.
    It is also possible to use common names in clog-tags, for example [clog]Peppered cory[/clog] will show up as Peppered cory. [back to question list]

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