My oto's fins are gone!

[safiredragon]

Hey all. My 12 gallon Eclipse aquarium houses 4 zebra danios and 2 otocinclus cats, as some of you already know. Recently I've noticed that one of my otos, the one who happens to be a bit younger and was a several months later addition to the tank, seems to have no fins at all! His tail, side, and pectoral fins are all gone down to the nub. My other oto's fins are fine. Are the other fish picking on him? Should I separate him? Other than this, he seems fine; he's very active and seems to be eating all right. What could be causing this and what can I do?

[mr gerbil]

Do you know what your water conditions are? Also, have you noticed any agressive behaviour towards this oto?

[safiredragon]

Unfortunately, I ran out of test strips awhile ago and haven't gotten around to buying more. >_>. I can't imagine much has changed, though, as all the other fish are doing just fine and have healthy fins. I haven't seen any aggressive behavior towards this oto, but I can't think of any other explanation besides his tankmates biting his fins off.

[Catmakemebark]

That was the same for my red fined shark. My mollies ate him for no reason. He was like 4 times their size too!! Plus he was fat! He just disappeared one day.

[mr gerbil]

Get the water tested. Things do change.

[Cottontail]

That's probably the problem. Not every fish in the tank has to be showing signs for something to be wrong. Things could be going wrong, and because he's the "runt" he's feeling it first. Please get it tested :).