Loaches Online Forum

I'm at a loss here. My 18 year old son has a 10 gallon tank that he takes good care of, but for some unknown reason he is unable to keep a pleco alive in his tank for more than a few days! So far we've lost 2 widemouth plecos (Chaetostoma sp.) and, as of today, a bristlenose pleco (Ancistrus Temminckii). All three plecos were apparently healthy when purchased, but all have died within a week or 2 for no obvious reason. To be clear, we've only stocked one pleco in the tank at a time, and we've waited several weeks between them before buying another, to insure that there wasn't an illness in the tank.

The tank is populated with 2 lemon tetras (Hyphessobrycon pulchripinnis), a black skirt and 2 white skirt tetras (Gymnocorymbus ternetzi), a diamond tetra (Moenkhausia pittieri), and 2 spotted cories (Corydorus agassizii). We haven't seen any signs of aggression from these fish, and they all seem healthy and content.

The fish are fed a mixed diet consisting mostly of flake food and shrimp pellets, with algae wafers and frozen bloodworms added from time to time. There is also a substantial growth of algae on most of the tank surfaces at this point, so I don't think that the plecos were lacking for food.

The water quality is (by my estimation and testing) good, and 25% water changes are done on a weekly basis. Currently the pH is at 7.5 (we have somewhat hard, alkaline tap water here - it causes more problems than it solves when I try to force the pH down to 7.0 so we leave it alone and the fish seem to be fine with it), ammonia is 0, nitrite is 0, and nitrate is at 20 ppm.

His tank conditions are nearly identical to mine, yet I don't have any trouble keeping my pleco alive. The only differences between our tanks that might be relevant in this situation are the plastic decorations he has in his tank. Could they possibly be toxic to the plecos?

I'm truly confused by this. If anyone can shed some light on this situation, I would sure appreciate it and so would my son.

I have heard of certain decorations that are toxic, what sort of decorations are in your son's tank?

Ask at the store. Many Loricariads are fasted before shipping, then have trouble resuming eating. There is some thought that the intestinal organisms die off when they are starved, then the fish cannot digest the food. If the fish have been at the store for more than a week and are eating, and plump this is good.

Thanks for the advice, Diana. I will talk to the folks at the store and see what they have to say. It is a good store that takes impeccable care of their fish, so I think they will be helpful. I suspect that if I ask them to hold a pleco for a couple of weeks to insure that he's healthy and feeding, they will.

As for the decorations, they were of the cheap, Walmart variety and have already been removed and replaced with PVC pipes. Not quite as pretty, but the fish seem to like them better and we know they won't harm the fish. my suspicion is that the decorations, having been made with low standards, may have had toxic paint. The plecos would have had the highest exposure, as they were sucking algae directly from the painted surfaces. That would explain why the other fish seem unaffected. I won't make the mistake of putting those in a tank again.

We've moved several platys into the tank, as they do a decent job of grazing on the thicker patches of algae and keeping the tank from being completely overrun. They are happily gorging themselves as we speak.

Just an update, after having removed the suspect decorations and waiting several weeks (and several water changes), we tried adding another pleco.

We decided to go with a clown pleco, and we picked out an active little guy that had been in the store for close to 2 weeks. We also put in some Malaysian driftwood, which we had failed to include before (no idea why not, stupidity perhaps?).

Long story short, my son's pleco has been healthy and apparently happy for a month now and his tank looks cleaner than ever.
Thanks again for the advice.

I am glad that problem was solved.
It sure seems to have been the decor. Unfortunately I have seen that before. Even things made for aquariums are not fish safe.

Monitor the conditions in the tank, it is getting a bit crowded.

Make sure the water is well oxygenated and has a decent flow to it. xxx

Thanks for the advice!

Indeed, it is well oxygenated, has good flow and strong filtration relative to the size of the tank.

The clown pleco that is currently residing in the tank has been in there for months and is showing every sign of being healthy and happy. As for the crowding: yes, we know that the tank is a bit overpopulated. This is a temporary issue, as we are waiting for a new, much larger, tank to cycle and then our fish populations will be shuffled around. In the mean time, a combination of frequent water changes, constant monitoring, and heavy filtration is keeping the water conditions good for the fish, and they are healthy and (as far as I can tell) happy.

If you are going to move all the fish to the new tank you can make sure to move all the bacteria, too, by moving the filter and the top layer of the substrate. A planted tank will help, the plants are great for removing nitrogen in the 3 most common forms we see in our tanks.

Actually, Diana, I've been using your excellent primer on fishless cycling (thank you). The new tank is nearly ready at this point, and I did indeed use a number of items (including a canister filter with all media) from a mature tank to seed the new tank with. I figure in about a week I'll be able to start slowly adding fish.

Not all of the fish will be getting moved, but enough so that the small tank will no longer be crowded.