Someone recommended I repost this here instead of under general help (sorry if this is frowned upon...):
I have a 10 gallon tank. The tank is in an office, and I put a lamp over it to heat it, so temperature varies from about 69 degrees in the morning after cooling all night to 74 degrees by the end of the day. Entirely freshwater, one filter. I make water changes with a vacuum/siphon about once a week, sometimes once every two weeks (my schedule is irregular and so are the water changes) and try to get as much nastiness out of the pebbles when I do.
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 because the one was trying to nibble almost constantly. My betta does have fin rot, which I'm currently trying to get rid of, but I don't think this factors into anything. (I have a thread about it here if you have any questions about it: http://www.tropicalfishkeeping.com/b...fin-rot-53651/
If I should get rid of the tetras for something less nibbley, do you have any recommendations on what type of fish I should get? Having two fish in a 10 gallon tank, especially when one never comes out in the light of day, seems a little bit overkill, but it seems like it would be better to have fewer rather than more.