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Ok, my sister has a five gallon tank, with a pleco, i know its a small tank for it but it was still pretty small. it also has 2 pristilla tetras, 2 cories. Its been setup for a little over two months. The water was fine for a month, but then yesterday i found the pleco floating dead on the top of the tank. I tested the water and the nitrate was at 200 ppm. I know that is really high. Why would the nitrate go up so high if it was fine for the last month. And the pleco probably dies from it, but its half of its tail was missing and it looked like his skin was eaten up. Now can nitrate do that or would the tetras actually do that.,

Nitrate: "A salt or ester of nitric acid."

Nitric Acid: "A corrosive liquid inorganic acid HNO3 used especially as an oxidizing agent, in nitrations, and in making organic compounds (as fertilizers, explosives, and dyes)."

Nitrate in high concentrations like 200ppm does indeed become corrosive, especially in small tanks where the water volume is low.

The trop died from an excess of waste, producing the nitrates, brought on by a lack of proper water changes.

I would guess the poor trop suffered badly before it died.

The average nitrate content should have been, for a small tank, around 10-20ppm.

--garyroland.

--Vero Beach, Florida.

Are you vacuuming the substrate in your tank? It's really unusual for nitrates to build up that much, even over the course of a month. I would suggest testing your tank at least weekly, and doing some water changes and gravel cleaning now. Nitrate at levels like that is very dangerous to fish, as you just found out.

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And when he gets to Heaven, to Saint Peter he will tell: "One more Marine reporting, Sir! I've served my time in Hell."

I did a water change yesterday, and put conditionor in and the nitrate went down but i will keep checking the water parameters

plecos produce 2x the bioload of other fish, so wheras for most fish you can caluclate 1 inch to 1 gallon, for plecos you have to 1/2 that, so you can fit less pleco in per gallon.

Bottom line - the tank was too small for the pleco and it was eaten alive by bacteria in its own waste.

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I like to think that whoever designed marine life was thinking of it as basically an entertainment medium. That would explain some of the things down there, some of the unearthly biological contraptions