Plecos keep dying

I have a 55l Aquanano with neons, tetras, drawf gourami, and a cory catfish. This is an aqua-nano which has the equivalent of a 3-tier filter built in to the back utilizing: 1) 3-stage foam filter, 2) foam bio-block, 3) active charcoal, 4) 1kg of ceramic rings (in that order). The water quality is nearly perfect although the nitrate isn't perfectly 0 (but it's close).

I'm a bit at a loss as to what's going on here. This tank has been running for several months now. There is an 18WPL light so there's plenty of grazing algae which I'm supplementing with pleco food. No one is picking on it, belly not sunken, actively hanging off the glass and busying about everywhere. Then, suddenly, dead. This has happened 5 times now. No medication has ever been used in this tank.

Twice the death occurred within a day or two of a water change so my running theory was that the sudden change in water temp after a change (or some other factor) had something to do with it.

Any ideas what could be missing here? In past tanks I always remember plecos being easy and robust. I had never had to bother with dedicated food before now. The rest of the tank diet is flake, pellet, and occasional bloodworms.

Pleco are very sensitive to even small ammonia spikes like after water changes. Thd dead pleco will have swollen belly and damaged gills. This is all I can think of for now.

Could be your active carbon,
This needs to be replaced(if you haven't already) frequently, as it can leach toxins when it's full

This is another possible as activated carbon can leach phosphate back into the water and kill plecos. Any time I use activated carbon I always remove it after 4 days.

Had a similar issue some time ago with my son's tank, couldn't for the life of me work it out!
Turned out to be the carbon as the lads above say, it was removed during a water change at one stage and I never had any more issues, 3 bristle nose in there now thriving!!!!

I had been wondering about the activated carbon. 4 days? No, I'm leaving it in for 3 weeks at a stint.

I'll remove it now and maybe give it a rest as the tank is established by now and shouldn't need it. I have an API master test kit on order which might reveal something in the future (using test strips currently).

I'm wondering about alternatives to plecos which would offer the same services. The 18w PL light causes a good amount of brown algae to form on the glass and decor. Currently I really see the plecos as mandatory as they just do such a brilliant job in keeping that in check. Can anyone recommend any alternatives?

Any time I use carbon its the rowa brand and it says remove it after 4 days. Maybe other brands are different.

Paul, I think you might be being overly cautious with your carbon usage. I was just reading again that really what it absorbs doesn't leech back in aquarium conditions. However if it isn't phosphorous free (which better brand might claim to have none of) that the phosphorous may leech. However I will admit I bought this carbon in bulk off eBay and have been leaving it in for 3 weeks. As the tank is established I think i'll just do without it and remove the variable from the equation.

One interesting note from reading about carbon was this:

There are several important toxins that activated carbon does not remove. Most notably, it does not move ammonia, nitrite or nitrate.

source: freshaquarium.about.com/od/filtermedia/a...-In-The-Aquarium.htm

JohnH wrote:

Just a couple of supplementary questions here, with your water top-ups (after which the deaths seem to occur) are you using water from hot water tank?

Just one more thought - brown algae mightn't be the most healthy food source for them, even though they are eating it, it might be that an improvement in light intensity (I do not know if your hood could accommodate a second light unit?) would help. Brown algae isn't always regarded as a sign of a 100% healthy environment within an aquarium. Oh yes, are these established fish or newcomers which are dying?

As well as pleco wafers you should offer a green food alternative too - a slice of cucumber or even a par-boiled Brussels Sprout (remove any uneaten after it's been in there for a day or so and replace with fresh supply) would help.

No, I don't use the hot water tank. But I'm also not being patient enough to let the water come to room temp so I have noticed a drop from 25C to 20C as the water is like ice this time of year. I know, I won't do that again.

Oh, I understand the brown algae isn't enough in this sized tank which is why i have the pleco food. But that is the reason why I feel I need a pleco.... unless there is an alternate algae eater which is more robust I should investigate.

I'll try the cucumber. Would nori do any good?

newkie wrote:

Paul, I think you might be being overly cautious with your carbon usage. I was just reading again that really what it absorbs doesn't leech back in aquarium conditions. However if it isn't phosphorous free (which better brand might claim to have none of) that the phosphorous may leech. However I will admit I bought this carbon in bulk off eBay and have been leaving it in for 3 weeks. As the tank is established I think i'll just do without it and remove the variable from the equation.

One interesting note from reading about carbon was this:

There are several important toxins that activated carbon does not remove. Most notably, it does not move ammonia, nitrite or nitrate.

source: freshaquarium.about.com/od/filtermedia/a...-In-The-Aquarium.htm

I only use carbon after I treat the tank with any medication like for white spot, the carbon is just to cleanup any left over meds. The rowa brand claims to be lowest in phosphorus. I remove it after 4/5 days. I know it wont remove ammonia or nitrites, it does a great job to polish water. I have large sail fin and royal pleco in one tank and BN and golden nugget in a smaller tank. Only time I lost all my plecos was after a filter cleanout not paying attention to water testing.
It worth getting the api test kit and checking water then, if your tank is running 4 to 6 weeks only it may not be fully cycled yet.

Only use Charcoal to remove meds after they have done their job.

H.

Tank is very small for a pleco how big were they.

Hi homer, whats the difference between activated carbon and charcoal?