6 month tank. 1-2ppm ammonia, 0 nitrite

I have a small 10 gallon tank that was started about 6 months ago. It contains 2 zebra danios, 2 bloodfin tetra, 2 cardinal tetra, clown pleco, and a very recent addition of few Amano shrimp (approximately 1.5 weeks ago). Until a couple of weeks ago my water chemistry was sitting at 0.25ppm ammonia, 0 nitrite, trace nitrate (this was just prior to the introduction of the amano shrimp). About two weeks ago we added some cherry shrimp (Prior to the amanos) which unfortunately got picked off by our danios within a week. I mention this because I wonder if there isn't a little shrimp body hiding somewhere, contributing to my high ammonia level. All the fish seem alright, as do our new amano shrimp. I have been attempting to rectify the high ammonia levels with daily 30% water changes for the last 5 days, to which the ammonia has remained steady, with nitrites nearly remaining at 0 (although it was .25 one day). Today I replaced the carbon filter in my aqueon quietflow 10 (it suggests being replaced every 4-6 weeks, which I have been doing). I also added a small amount of ammo-lock to the water (approximately half the dose suggested for 10 gal.) when I had seen the ammonia spike. Sorry for the long winded background, but it might help in answering my mains questions?

1. Do you think the ammonia spike to about 1ppm is resulting from the change/increase in bioload of the tank? Or is it more likely to be from a bit of overfeeding or possible dead cherry shrimp hiding somewhere out of view?

2. I have heard mixed reviews about using ammo-lock (I know it's a very short term solution). Should I continue to use this product?

3. I plan on continuing daily 30% (or twice daily 15-20%) water changes to try to get my ammonia in check. Are there any other suggestions?

4. Are the carbon cartridge changes to my tank harmful? I am also hesitant to replace them because of the amount of the necessary bacteria they must hold, despite them claiming to have a "bio-holster" that contains the bacteria.

Also:

I am aware of the schooling of tetras. Originally we had 5 bloodfin tetra, very early on when we got the tank they died. Our pet store no longer stocks that type, so they suggested something comparable tetra wise (in an attempt to see if they would school), which is how we ended up with the cardinal tetra. Both the bloodfins and the cardinal tetra do seem to stay quite close to each other.

I know most plecos grow too large for 10 gal. tanks (I had a common pleco in my old 90 gal. for many years and it was huge). It is my understanding the panaqolus maccus doesn't generally get larger than 3 - 3.5 inches full grown, and minimum tank size should be 10 gal. (http://en.wikipedia.org/wiki/Panaqolus_maccus, and my local pet store fish guy). It is a little small, but he seems to be fine in there. He's been in there since the start of the tank.

Our ammonia levels when we had our cherry shrimp never rose above 0.25ppm. And were visibly being picked off by the zebra danios.


Also, our tank was cycled with our zebra danio intially, and no fish were added until both the ammonia, and nitrites were 0.

BettaFishMommy said:

sounds like the tank and the filter are just not large enough for your bio-load. either reduce your fish and invert numbers or upgrade to a larger tank and filter. plecos are very messy and that could easily be contributing to the raised ammonia.

i never use ammo-lock or comparable products. a good old water change and some Prime (a dechlorinator made by SeaChem) are all you need.

changing out the filter cartridge could be lending to the ammonia problem, since there isn't much media to start with in a cartridge style filter, and replacing the cartridge could be taking away a good portion of the bacteria. what i do for all cartridge style filters is use a block of sponge instead, cut to fit in the box of the filter. this means you can rinse the sponge (in a bucket of tank water) and re-use it, without harming your bacteria colony.

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I have plans for upgrading to a 29 gal possibly in the future, do you think a larger/better filter might improve the situation, would you suggest the block sponge attempt first or to go for the larger filter to begin with? The pleco is quite messy, but I have attempted to fairly diligent in removing as much of that as possible with the weekly + cleanings. The clown pleco has been in there for at least 5.5 months, and the ammonia levels have remained very low to nil (0.25 to zero) during that period which it was just the tetra/danio/pleco, so I'm not sure if he's the prime factor.

XanAvaloni said:

+1 what BettaMom said. I think the tank would be fine if it weren't for the pleco, or at least that's the one single fish that pushes things over the edge. You say you had an ammonia level of .25 BEFORE the incident, indicating the situation was already bad before the addition of more stock.

Fastest solution is to remove the pleco (return, rehome, separate tank, whatever.) If that is not something you can or wish to do then other steps need to be taken. The filter seems inadequate for the task. I would get another filter, at least a 20 or if you have space a 30. Add it while leaving the existing 10 in place until it is cycled, or for that matter forever. Too much filtration is never a problem.

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I've grown quite attached to the pleco, and a larger tank isn't in the cards immediately (moving houses in the not so distant future, and I just don't really have a good spot for something larger at the moment). I will look into purchasing another larger filter however, do you have any types/brands you would suggest?

SubRosa said:

What is the pH of the tank? As it gets lower nitrification (the conversion of ammonia to nitrite and then nitrate) becomes less efficient. Once you get under about 6.5 ammonia is no longer oxidized and begins to acumulate. Fortunately at those lower pH levels the ammonia is converted naturally to much less toxic ammonium.

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The pH of the tank (last a checked) was at 7.8, and has been consistent between 7.8-7.9

SubRosa said:

That's pretty much the optimum level for nitrification. You need more nitrifying capacity. For maximum processing of ammonia nothing, and I do mean nothing beats a bio wheel. There may be other arguments against the Penguin and Emperor filter lines, but for sheer nitrifying capability they win over all other brands of hob filters. A Penguin 200 would fill the bill nicely.

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Would a 200 fit on my 10 gal?