I have a 10 gallon tank. It has comfortably housed a betta fish and a plecostomus (clown pleco) for about a year and they get along fine--the pleco has a lot of dark hiding places, some wood to eat, etc. and the betta stays out of his way and is disinterested.
About a week ago I bought three black skirt tetras because the tank looked really empty. The employee said they would get along fine with the betta and the betta would get along fine with them, and for the most part he was right. There is one tetra (the smallest), however, who has been nipping at the betta's fins (the others may be nipping as well but I haven't caught them). I looked up some info on tetras and saw a warning that if you did not have enough tetras in your tank they may get nippy. The website suggested a minimum of 5 tetras.
My questions are, first of all, would having 5 tetras, one betta, and one pleco be too much for a 10 gal tank? If not, will getting 2 more tetras really stop the fin nipping? I will happily get 2 more tetras if it will stop this behavior, but if not there is no point and I will have to get rid of the tetras. My betta was the first fish and I feel like he's losing his territory. I feel awful about it.
Also, I've been trying to feed the tetras flake food but I haven't seen them eat any of it at all yet. The betta is fed primarily pellet food and the pleco gets algae wafers (and sometimes vegetables). Is it at all possible that hunger could be a part of this?
For now the tetras are 'quarantined' in an extra 5 gallon tank I had set aside.
On a completely different topic... the betta has had a nasty case of fin rot that I can't get rid of. I tried Maracyn first with no success and have been trying Melafix for about a week with no apparent effect. Does anyone have any recommendations?
Thanks in advance.