Chronic Cory fin rot problems

[Mol_PMB]

These are the two videos I used to set up the tank decor, and as you can see they both feature rapid flow, sand, wood and leaf litter. There's also a sequence with small pebbles and a wavy-leaved plant similar to the Echinodorus I selected:

https://www.youtube.com/watch?v=yGx__0JDZls (from about 2:45 onwards)
https://www.youtube.com/watch?v=cLwvUXC3dHY

[dw1305]

Hi all,

These are the two videos I used to set up the tank decor, and as you can see they both feature rapid flow, sand, wood and leaf litter. There's also a sequence with small pebbles and a wavy-leaved plant similar to the Echinodorus I selected:

Thank you for the video links, I enjoyed them, and your tank look very similar to the rivers.

I have no other suggestions to make, other than the Alder cones, hopefully things will sort themselves out.

Alnus glutinosa is common by streams and lakes etc. and you sometimes see Alnus cordata used as a street tree in supermarket car parks etc. It stays green very late in the year and has much bigger "cones".

I've always collected my own Alnus cones (from all, or any, of A. glutinosa, A. incana and A. cordata), but I know "A World of Fish" sells them in the UK (on Ebay), and he has been very good to do business with when I've bought fish food etc.

cheers Darrel

[Mol_PMB]

Thanks Darrel.

I have collected some more oak and beech leaves and will spend this evening washing, drying and storing them for the coming season. I'll boil up the tatty leaves to make some 'Orinoco tea' as well, and use some of that at the next water change for this tank to add some tannins. I'll go looking for alder cones this weekend. I'd prefer to collect them myself if I can but thanks for the enay suggestion too.

I'm hoping the fish will improve as a consequence of one of the changes I've made, and I will update this thread when I have some more news.

For now, here's a nice photo of two of my C.oiapoquensis when I first got them over 2 years ago. I really hope I can get them back to this condition.

Cheers, Paul

[Mol_PMB]

I have increased the frequency of water changes and also increased feeding a little and treated them to some live Grindal worms in addition to the usual variety of pellets and frozen.
Yesterday I did a water change with tannin-stained water (from boiling fallen oak and beech leaves). Conductivity now down to 210us.
The fish became more active than before; I'm not sure if this was caused by the change in water chemistry or the fact that the light doesn't penetrate so well through the brown water, so maybe they feel less exposed.
I'll do another water change on Saturday with some more brown water and see where we go from there.
I'll probably also get some more Corydoras for this tank on Saturday but they will initially go into QT.

[josecatala]

Hello everyone,

I am having the same issue in one of my tanks. I currently have 9 tanks running with fish and all have cories in them. Just my one tank, 72 gallon, is having this problem. I have 7 green/bronze cories and 2 Sterbai. One of the Sterbai has it really bad, where most of his tail is gone. Most have the barbles really short. I've tried several meds for fin and tail rot, but nothing seems to get rid of it all together. None of the other tanks are having fin and tail rot issues.

this tank has been running for almost 2 years. Sand bottom, driftwood and some rocks. Fully planted. I dose daily with seachem's excel, and Iron. Every third day seachem's flourish, and twice a week, seachem's potassium. Temp is around 80 F. I am pretty religious on the water changes. R/O conditioned back with Discus trace. 20% weekly.

I'm very interested to see what you try and if its successful.

[Mol_PMB]

Thanks - that's really interesting. It seems like there's some combination of parameters that doesn't work well with Cories. Hoops fully we can understand it and do better with them in future.

[Mol_PMB]

Well, I'm doing 3x30% water changes a week on the tank now, and adding tannins from oak or beech leaves, or alder cones.
I'm also feeding a bit more frequently with smaller foods, plenty of live grindal worms, bloodworms etc.

I bought some new fish for this tank on Saturday; a group of 5 juvenile locally-bred Cory oiapoquensis (which are in the QT) and there was just one wild-caught Cory amapaensis available. I bought that too because it (he?) was a beauty, and he's gone straight into the Oiapoque tank because he was 3 times the size of the young oiapoquensis.

Since the changes in water parameters I have noticed much more activity in the tank which I hope is a good sign.

There hasn't yet been a noticeable improvement in the fins of the oiapoquensis but I hope they will improve.

[Mol_PMB]

An update:
I have been doing 30% water changes twice a week (instead of once a week) and adding tannins, leaves and alder cones. I've been feeding more heavily too, continuing with a mixture of pellet, frozen and live foods.
I adjusted the filter pipework so that the velocity and noise has been reduced although the flow rate remains the same.
I've added the 5 new small C.oiapoquensis and the solitary adult C.amapaensis.
I have been adding a dose of Melafix at alternate water changes. I have reduced the additions of plant fertiliser.
All the fish seem to be doing well with some regrowth of damaged fins, though they're not all perfect yet.
Perhaps linked to the increased feeding, there is an increase in brown detritus, sometimes suspended in the water. I've been doing my best to siphon this up at water changes.
There has been an increase in the 'playfulness' of the fish, with groups chasing each other around. This usually happens with groups of one species but sometimes with more than one species. The C.amapaensis seems well at home with the 3 C.condiscipulus; though of course I wish I could get more of both! The 5 small C.oiapoquensis have visibly grown over the last few weeks and are playing with their elder brethren.

[TwoTankAmin]

A couple of quick thoughts here. I agree with those saying nitrates are likely not the issue for the reasons mentioned. I think the problem is a bacterial one. I have found fin rot usually either has fungal or bacterial cause and often both will be present. But in the case of fungus you can clearly see that component. The problem is where you live and what that means for the availability of meds.

The fact that the fin rot is persistent argues to me that the cause must also be persistent. Melafix, imo, is useless for this sort of situation. I am not sure what to suggest as it is not easy to get real fish meds in the UK. Here I would try a round of an antibiotic such as Erythromycin which is one of several I keep in my fish medicine kit. I have never had issues with it harming the biological filter in tanks, especially in a decently planted tank.

One note re Rooibos tea. This stuff is great, it will stain your water like tannins, it will release some very beneficial chemicals but it will not release much in the way of tannins. It is not actually a tea. Rooibos comes from the plant, Aspalathus linearis, a legume in the family Fabaceae- it is related to peas and beans. For fish keeping we are interested in the plant phenolic compounds which act as antioxidants and also as antibacterials (it doesn’t harm filters). This is similar to the humic acids found in natural “tea” stained waters which have similar phenolics. Oak leaves contain a lot of the plant phenolic quercetin (derived from the Latin name for the oak tree, Quercus robur) and rooibos also contains some quercetin plus the compound aspalathin, which is closely related to quercetin.

Rooibos will not lower pH nor soften water. it may actually bump your pH .1 or so. I have used it as part of a mix of things in a tank for wild Altum angels which includes IAL, alder cones and occasionally some peat. I have actually tried using rooibos as a med with mixed results. The nice thing about rooibos is you can brew it and then pour it into a tank. A lot less messy than the other things, BTW, rooibos is a popular tea for people and it has health benefits for us as well. I have not tried it however.

[Mol_PMB]

Thanks TTA for the detailed suggestions - that's a good tip and I'll try the Rooibos.

[josecatala]

Hi,

Just an update to my situation. My 2 Sterbai past on...... I tried Seachem's Paraguard for 7 days as suggested treatment for Fin and Tail Rot. the other 7 seemed to be doing fine, and I thought I may have found the cure, but I noticed today that one of them seem to be showing signs again. I agree it has to me something that is in the setup. A while back I did try Erythromycin as directed and there was a temporary reprieve. All of them seem to be looking for food and eating. I thought about adding Catappa leaves..... I'm interested to see what your results are with Rooibos.

Thanks to all of you and I will keep you posted.

[bekateen]

Good luck josecatala and Mol_PMB.

Cheers, Eric

[ErikO]

I had similar problems with wild caught Sterbai. No problems with their offspring or other locally raised Sterbai.

[Mol_PMB]

Happily there has been a great deal of improvement. All but one of the fish now have normal fins, that one still isn't perfect but has definitely improved in appearance and behaviour.

Here's a photo of feeding time in the tank with many of the fish visible in a mixed species group.

[Daphnia]

Hi, I'm new to this forum and have just seen this post, so, sorry for the late reply. From my experience (a year with 6 Bronze Corys in 30 l planted aquarium in Wales, UK), as soon as nitrate went as high as yours (40 ppm) some of my Corys were guaranteed to have a skin problem of fungal origin, e.g., eroded edge of fin, split fin or a tuft of Saprolegnia. All I needed to do was to perform water changes to reduce nitrate to 5-10 ppm - and all the problems always disappeared in few days without any medical treatment. For the past three months I have kept such low nitrate level, by changing 20% water twice a week, and my pets look happy (even re-growing barbels nipped off a year ago by aggressive serpae-tetras, which I bought by a lack of knowledge and then returned to the shop). I also noticed that the use of a very soft Welsh tap-water (GH & KH undetectable with Tetra test strip) in aquarium favoured outbreaks of fungal pathogens, while creation of a moderately soft water (GH 7, KH 5, which I achieve by additions of CaCO3, MgSO4 and micro-elements of Fe, B, K, Na, Cl) provides for a stable microbial flora in my aquarium. I regularly add autumn leaves (oak, beach, elm and cherry), alder cones and occasionally 1/3 of cinnamon stick.

[Mol_PMB]

Thanks - that's interesting. I also have very soft water (GH 1.5, KH 0.6) but generally keep it that way in most tanks as it is similar to the natural habitat of many of my fish. Perhaps I should add a little coral gravel to raise the hardness a bit?

[Daphnia]

And what about your fish health now? If everything is healthy and stable, I'd just keep it that way, whatever it is based on. We should bear in mind that we keep different species of Corys that may have slightly different requirements. As far as I know, most natural rivers in Brazil don't have such a low hardness as our tap water, which is actually a locally collected rain-water, slightly chlorinated and often contaminated with Cu from copper pipework (the Cu and not Cl2 is the reason why I have to add Bioactive Tapsafe to my water). I checked some data on natural river waters in the internet and also put Tetra Test strip into the river in front of my house, which is highly rated for water quality. The Arth River water test showed: NO3=5, No2=0, GH=7, KH=5, pH=7 - which I decided to set as my target parameters for aquarium. I don't know about coral gravel. I've bought medically pure CaCO3 powder from on-line health store - monthly addition of about 1 gram powder wrapped in a piece of nylon stocking in-between filter sponges gives me KH 5 and PH 7. I've also come across a credible opinion that adding CaCO3 without MgCO3 could be even harmful, as that upsets osmotic nutrient balance in both plants and fish. So, I'm adding also small quantities of pure MgSO4 (Epsom Salt from chemists), Fe, B, K ("I love fish" Plant Fertilizer) and NaCl (sea salt, just one grain a fortnight as a micronutrient), plus whatever micronutrients comes from autumn leaves and alder cones. Sorry I can't tell you exact recipe, just a "cf. idea". And, back to the beginning, low NO3 (5-10) is crucial, according to my experience.

[Mol_PMB]

I've been doing 30% water changes twice a week and have not been dosing plant fertilisers. Two fish still have damaged dorsal fins (which haven't really got better) but their other fins are fine. All the other fish are fine. Apart from the fins, there is no obvious difference in the health of the two fish.
I've got many of the chemicals you mention as I also run a marine tank. I think you're right though, I should also focus on more water changes and keeping the nitrate down. I probably over-feed this tank too as there is an abundance of snails.
Most of my other tanks run with similar parameters and the other spcies of Corydoras I keep in them don't have such problems.
Thanks for your thoughts.
Paul

[Daphnia]

Thanks you, Paul, for explaining your situation, it is very useful for me to know about your experience, for there aren't many aquarists dealing with so soft tapwaters like ours.
If all your fish are fine, except the two, then it looks like the two fish just have a weaker immunity than the others. Have you tried to feed them up with some live foods? - Known as the best source of essential amino acids and whatever fishes need to be healthy, and I suppose that at least bloodworm should be available in such a big city as Manchester. Here I am in a very rural place and local pet stores are quite poor in fish supplies. I'd love to provide some natural treats for mine, see them happily slurping up worms... But so far I've just started with home-bred daphnia. If you can pass a comment on that, please, switch to my subject "Live daphnia for Corydoras".
Best regards,
Inga

[Mol_PMB]

Hi Inga,
Thanks again

Yes, they get live foods quite regularly. I keep cultures of Microworms, Grindalworms, Daphnia, Moina, Artemia, Copepods and Rotifers. Sometimes I buy bloodworms, blackworms, whiteworms, tubifex and 'glassworms' (mosquito larvae). This tank of Corydoras gets live Grindalworms about two or three times a week, with other feeds being JMC high-protein catfish pellets or frozen bloodworms. My Cories love worms but and other foods that sink, but don't tend to chase the live foods that swim.

I've had a bit of a shift around recently and have now got three tanks of Corydoras; I tend to keep them in groups of similar-looking species:
90L: 8 C. oiapoquensis, 3 condiscipulus and 1 amapaensis (the one with the fin problems)
100L: 13 C. melini, 3 simulatus, 2 C016 (plus some Copella meinkeni and two juvenile Pangio loaches)
54L: 6 C. burgessi plus fry (spawning almost weekly at the moment)
Nearly forgot, all my tanks also have at least one juvenile Farlowella vittata as a glass-cleaner. I'm over-run with them!

I believe that all my Corydoras are wild-caught except some of the oiapoquensis (from a local breeder), one melini (born here) and the growing herd of burgessi fry.

Regards,
Paul

[Daphnia]

Sounds great. I have looked up the images of your fish species in the internet, very exotic indeed. You are lucky. Adaptation of new species for captivity is so interesting, challenging and important for conservation of rare species, some of which are not yet identified, but already endangered - I've read some articles in Practical Fishkeeping. I do feel amazed.
Could you, please, advise me on a type of worm that I can grow in my garden/polytunnel during summer? (our house is really small and I am not allowed to bring in worms.) and, if such worms exist, could you send me some eggs by post? I don't need many, as I only have 10 small fish (6 Bronze Corys + 4 Harlequin Rasboras), which I want to treat with live food twice a week for mutual entertainment and supporting their health (with no intention to breed, as there is no space for that here).

[Mol_PMB]

I'd say you could keep microworms or grindal worms in those conditions during summer.

Here's a thread I wrote (on a different forum) which includes a description of how I keep both of these types of worms:
http://www.tropicalfishforums.co.uk/ind ... 402.0.html
The challenge when keeping them in the garden would be to keep the other wildlife out so you would need some very fine mesh over the holes in the boxes.

I could easily send you small packets of either (or both) types of live worms to get you started; you'll need to get the rest of the ingredients.

Drop me a personal message with your address and I'll send some this weekend.

Cheers,
Paul

[Daphnia]

Hi Paul, I've prepared homes for the creatures. I've also enjoyed the videos of Corys in their natural habitat you posted earlier. And I've tried to think of possible explanations why a slight mineralization of water has worked for my aquarium. There are two:
1) It is believed that KH > 80 ppm (4.5 d) is needed for sufficient buffering capacity in planted aquaria to prevent pH swings day-night due to CO2 coming from respiration of plants at night. Such pH swings can stress fish, at least weaker individuals [info from the internet].
2) In soil science [my profession] the biological activity of soil is characterized by fungal:bacterial (F:B) ratio, and the lower soil pH the higher this ratio. Just an idea, what if there is a similar interplay in aquaria, with F="bad" fungal pathogens, b="good" nitrogen bacteria (lower pH - more pathogens?). This suggestion seems to contradict the fact that microflora copes well in soft acidic waters of South America. However, maybe just our commercial N-cycle bacteria (designed for average H parameters, would that matter?) get sometimes outcompeted by local fungal pathogens in soft acidic waters. Another observation on F:B ratio comes from my garden: I've successfully cured fungal diseases of few plants by dressing soil with CaCO3:MgSO4=3:1.

[Mol_PMB]

I won't get a chance to get to the post office today, but I'll send them to you tomorrow. Hope that's OK.
Cheers,
Paul

[Daphnia]

Hi Paul,
Of course, tomorrow or so, will be fine. Just drop me a message, please, when you manage to send them - and I'll be waiting for the postman the next days.
Maybe my F:B ratio hypothesis sounds crazy, but I'd appreciate if you tell me exactly what you think, doesn't matter - for or against - I only want to find the truth for myself. I think that good and bad microorganisms are in constant competition for colonising every substrate in aquarium (filter, gravel, plants, fish skin), and if the good ones are encouraged to squeeze the bad ones out of the water completely, then fish has a better chance to supress their skin pests by their own immunity. Medications used to eliminate the baddies can also stress fish and thus undermine their immune response. A small and gradual increase in hardness, as a temporary alternative remedy, should not cause as much stress as medications, am I wrong? By the way, what are your impressions from using phenoxyethanol (Interpet Anti Fungus and Finrot)? Did you notice any side effects? Nobody was too sedated?
Best regards,
Inga

[dw1305]

Hi all,

It is believed that KH > 80 ppm (4.5 d) is needed for sufficient buffering capacity in planted aquaria to prevent pH swings day-night due to CO2 coming from respiration of plants at night. Such pH swings can stress fish, at least weaker individuals.......

It isn't actually true for fish from soft water.

Tanks with some dKH are easier to manage, but you will always get some diurnal variations in pH in planted tanks, even ones with heavily carbonate buffered water. Changes in pH caused by changes in the oxygen:CO2 ratio don't actually change the alkalinity of the water, you've just moved the CO2~HCO3-~2CO3~pH equilibrium point.

I only keep planted tanks, because plants massively help with water quality management.

Fish from soft water will always experience fluctuations in pH and, as you move towards pure H2O, pH becomes a fairly meaningless parameter.

The only way to ensure a really stable pH is to use a pH buffer, (usually based on NaH2PO4:Na2HPO4 (conjugated acid and base)), and that is a pointless, and self-defeating, approach.

2) In soil science [my profession] the biological activity of soil is characterized by fungal:bacterial (F:B) ratio, and the lower soil pH the higher this ratio. Just an idea, what if there is a similar interplay in aquaria, with F="bad" fungal pathogens, b="good" nitrogen bacteria (lower pH - more pathogens?). This suggestion seems to contradict the fact that microflora copes well in soft acidic waters of South America. However, maybe just our commercial N-cycle bacteria (designed for average H parameters, would that matter?) get sometimes outcompeted by local fungal pathogens in soft acidic waters. Another observation on F:B ratio comes from my garden: I've successfully cured fungal diseases of few plants by dressing soil with CaCO3:MgSO4=3:1.

Very soft, acidic "black water" has a very low microbial load, and that is one of the reasons that black-water fish are difficult to keep in harder water.

There is quite a lot of recent (RNA based) work on the nitrifying organisms in aquarium filters, and it has shown that these communities are a lot more diverse than had initially been suggested.

You could have a look at "PlanetCatfish: Cycling Question"(viewtopic.php?f=4&t=41965)> and "PlanetCatfish:Using deep gravel...." (viewtopic.php?f=4&t=41038) for a more in depth discussion.

cheers Darrel

[Daphnia]

Thanks again, Darrel! Hydrobiochemistry discussions in these links are really in depth, very interesting and I'll have to spend more time on those. There is a similar tendency in soil science to reveal more and more complex interactions in soil biota. I still don't understand, what goes on in my aquarium with all those minerals, but I will try for experiment to gradually decrease my complex mineralization. After all, it is likely that my fish used to have skin problems because of lowered immunity due to a lack of nutritious food, and there was nothing to do with hydrobiochemistry.

[Mol_PMB]

Thanks Darrel!

[dw1305]

Hi all,

Thanks again, Darrel! Hydrobiochemistry discussions in these links are really in depth, very interesting and I'll have to spend more time on those. There is a similar tendency in soil science to reveal more and more complex interactions in soil biota. I still don't understand, what goes on in my aquarium with all those minerals, but I will try for experiment to gradually decrease my complex mineralization. After all, it is likely that my fish used to have skin problems because of lowered immunity due to a lack of nutritious food, and there was nothing to do with hydrobiochemistry.

The simple answer is that we just don't know what is happening in the tank.

Diana Walstad has some data in "Ecology of the planted aquarium" (if you don't have a copy I would strongly recommend it)
(https://www.amazon.co.uk/d/Books/Ecolog ... 0967377366) and there are articles by Dr Stephan Tanner (http://www.swisstropicals.com/library/a ... iltration/) & Dr Tim Hovanec (http://www.alltropicalfish.com/saltwate ... a-revealed) & (http://www.drtimsaquatics.com/resources ... ogen-cycle).

There has been quite a lot of scientific work of "constructed wetlands" for waste water treatment, some of which specifically deal with aquaculture, and we could conjecture that similar processes are likely to be occurring in planted tanks.

cheers Darrel

[Mol_PMB]

Interesting stuff, many thanks!

Happily there are no fin rot problems in my Cory burgessi tank, although I do find that the majority of eggs go fungussy. Here's a cute shot of the only survivor from their first spawn (which I didn't segregate). I have five more half-inch fry from a more recent spawn in the nursery and hoping the adults spawn again soon.