Shane's World Right Arrow ReproductionRight Arrow Pleco Breeding Techniques

Article © Larry Vires, uploaded January 01, 2002.

Probably the most misunderstood thing about breeding plecos is their diet. I am not aware of any true herbivores within this family. All need at least a minimal amount of protein in their diet in order to thrive and spawn as often as they would be capable. There are several diets which can allow this, but they can normally, with minor exception, be prescribed for each genus.

There seems to be a lot of confusion about what can and can't be used as a vegetable based feed. I have used several different types of fruits and vegetables over the years. It would be nearly impossible to list all of the accepted ones. I have found that green beans, sweet potatoes, zucchini, kale, and cucumber are all acceptable foods. I have also fed apples and mangos and they seemed to be accepted on varying degrees. It seems that the wood eaters, Peckoltia and Panaque, enjoy chewing on apple and sweet potatoes. At the same time, Ancistrus, and those genera with less defined teeth, go for the softer foods.

Ancistrus are predominantly omnivores with only a mild need for protein in their diet. By my best estimate, a 22 percent protein diet is the best suited for this genus. This does not apply to L34 or L255 since they are primarily carnivores. The remainder of their diet should be various vegetables. Most any kitchen vegetable will work fine, but some appear to be better than others. It is beyond the scope of this lecture to define which are better and which have adverse affects on the water or fish. This is discussed at detail at nearly every catfish site out there and can be researched rather easily. As my personal preference, I simply use canned green beans. However, it should more likely be rounded out with multiple vegetables.

Peckoltia and Panaque species have about the same requirements, but should also be surrounded in pieces of soft driftwood. A very large part of their diet is wood and without it, they will be hard pressed to develop properly and are very prone to "unexplained" deaths. I've done a minor amount of lab research on this topic and the preliminary results would indicate that they are reliant on a huge amount of their energy requirements to be met by an enteric bacteria which has the ability to break down the lignin in the wood not only for the interior energy available, but also for the energy from the lignin bonded in the cell wall. Suffice it to say, they will most likely not breed, but may be able to survive, without wood in the tank.

Hypancistrus and Baryancistrus are primarily carnivorous. The vast majority of their diet should consist of live or frozen foods. This can be rounded out by feeding any of the available carnivore pellets and an occasional addition of a good spirulina pellet. The addition of these prepared foods should not be overlooked since they provide a good source for vitamins which can be missing from an entirely live food diet.

Once you have gotten the fish eating a proper diet, the next step in getting a successful spawn is the substrate. Sturisoma, Lamontichthys, and several others really don't need a specific surface and will use the tank walls or floor as a substrate. Ancistrus are not nearly as picky about their spawning site. I have used everything from PVC to turned over flower pots and even had a single spawn without a cave being used. With that having been said, there are preferences for their substrate which simply apply to the following formula. The entrance of the cave is most preferably a square or rectangular hole which is approximately the size of the males body at the start of the pectoral fin rays.

The vast majority of the family fits into the following class. These fish need either properly designed caves or places made available for them to build their own. That is simply accomplished in one of 3 ways and will depend on the species being worked with. Some research, or trial and error, is required, but can normally be assumed based upon the genus with a little looking into the fish.

The majority of the species will need a properly sized cave made for them. There are 2 different formulas which apply here. The first, and one I've used most is a cave which is the same height as the males body, with only a slight amount of room for the dorsal fin. The length is 1 and 1/2 times the SL of the male and the width is the size of the males body plus 1/2 to 1 full pectoral fin. This makes for a very tight fitting cave and is normally used when the species being worked with has an excessive deterrence to light or is likely to dislodge the spawn before it hatches. The other formula is similar, but gives room for the male to extend the dorsal approximately half way. This is useful for Peckoltia and dwarf Panaque species. Because of their stocky build, they seem to be more comfortable in this type of cave and do not like to use the first version.

The third version is to allow the fish to make a cave for themselves. I can't take credit for coming up with this technique, but it was truly genius. This primarily applies to Chaetostoma species, but Zonancistrus L52 and some Ancistrus species have also made use of it in my tanks. The design is simple. I take a gallon milk jug and cut it down to about 4 inches deep. The top is thrown away, and the bottom is filled to just below the rim with a small aquarium gravel. On top of the gravel, I lay a piece of slate which just covers half the gravel. The fish burrow themselves under the slate and create a small, covered spawning pit to their own specifications. This is not a preferred spawning method. It takes quite some time for males to catch on to what they are supposed to do. When attempting this as a possibility, I always add a couple pieces of properly sized PVC to allow them an option. More often than not, they will use the PVC, but some males seem to require that they dig their own cave.

Sexing most species is quite simple when you know what you are looking for. The majority of species can be sexed by the presence of odontodes on the fins, posterior, interopercular, or sides of the head. This will vary with the species being worked with, but can be easily researched by looking at good photos of mature individuals. More often than not, the fish you're working with will show strong enough signs of their sex that research won't be required.

If this technique doesn't apply to the species you're working with, the fish will either have to be vent checked or scrutinized for proportional differences in the shape of the body and head. Both of these methods require that the fish are mature and you should have several specimens to compare. Vent checking is the easiest of the two. The fish are simply viewed from below, with a magnifying glass if necessary. The vent of a mature female has a rounded shape to it and may be distended if she is ripe with eggs. Most females will show an extreme bulge around the vent if they are nearly ready to spawn. Males can be a little more difficult depending upon the species. The vent will be smaller and has a flap of muscle that lays over it and gives it a rod shape. I'm not completely sure on the evolutional reason for the muscle there, but believe it is to direct the sperm back into the cave toward the eggs as they are being laid.

In order to compare shapes of the fish for sexing, the fish have to be mature. This just can't be done reliably before then. Males appear to get a great deal of detail in the shape of their head when compared side-by-side with females. This is to include several depressions and peaks in the profile of the head. In species where this applies, the female normally has a very rounded head without much detail to the shape.

Once you have established that you have full grown breeders, it is time to separate them out into colonies. These colonies should consist of a single male and between 2 and 5 females depending upon the species. Pairs can also be done, but it is a much slower method. The colony method will insure a better chance of a female in spawning condition to be present when the fish are triggered. Within a large colony, the bigger females are normally the ones that spawn most often. I'm unsure if this is caused by them running the other females away from available food, or simple mate selection by the male. I am more inclined to think the former since the smaller females can normally be caught up with the larger females if more food is introduced at each feeding and spread evenly across the tank.

Once all these requirements have been taken care of, it is now time to trigger the spawn. The vast majority of species need nothing more than a mild rainy season type trigger. This means to keep the tank clean of excess waste, but do nothing to the water in the form of water changes or chemical additives to control pH or anything else. After anywhere from a week to 3 months after starting, 30 percent daily water changes are began using very soft, neutral to slightly acidic water. The water changes should also drop the temperature by a few degrees. The tank heater is then allowed to bring the temp back to its normal setting. At no point during this trigger should the fish be starved. Feedings are increased when the water changes are done. At the same time, some source of current can, and often needs to, be added around the males selected cave. This has a habit of not only getting the males more interested in the cave, but also seems to attract females to the vicinity. The water changes should only be done for one week at a time and then dropped off to just enough to keep the waste out of the tank for another week with the temperature remaining stable. Most normally the fish will decide to spawn during this first break in the fluctuations. If not, the heavy water changes should begin again the following week. This cycle can take a month or more to get some species to get started, but once they have started should be able to continue with only minor maintenance. The water parameters should not be allowed to drift too far from those present when the first spawning took place since a drastic change can break the females spawning cycle and the process has to be started over.

The amount of current seems to vary quite a bit for each species. Panaque maccus doesn't seem to need a great deal if they are given enough circulation to keep the oxyegen levels high. That of course is going to depend upon the temperature, but should be maintained as close to saturation as possible for all species within the family. Most of the Hypancistrus and Peckoltia I've worked with seemed to be more attracted to currents as a parameter for choosing a nesting site.

That covers a large majority of what is done to breed plecos. I am going to drop off the topic at this point and will cover the hatching and raising of the fry in a later lecture. I can now take any questions.

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