Unfriendly tankmates, tetra nipping betta fins

six

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.

Calmwaters

Getting two more may or may not help in the fin nipping. Personally I would take them back and get some other fish that is not known for fin nipping.
As for the fin rot I would suggest you post about it in our betta section they are real nice over there and very helpful. I have kept bettas for a long time but its been so long since I had to deal with fin rot I can not remember what to do for it. Do you keep any aquarium salt in the water? Also do you do weekly water changes? I know those are very important for the health of the betta.

Byron

My only comment on the fin rot is that it may well have been caused by the nipping, and removing the offending fish will assist in a cure.

To the other issue, I would not keep other mid-water fish with a Betta. It does not matter what fish you try, fin nipping is a risk. Even fish that normally would never nip fins can find a Betta too tempting. You might want to consider the 5g as the Betta's home, which would allow you to have other fish in the 10g.

With respect to numbers, shoaling fish--which includes all characins (tetra, pencilfish, hatchetfish), most cyprinids (danio, rasbora, barbs, loaches) and many catfish (corys)--need to be in a group for several reasons. With characins and cyprinids, aggression is one common reason. The larger the group, the less chance of fin nipping to other fish, though some will still nip each other (Tiger Barb, Serpae Tetra are notorious for this). The size of aquarium also has a bearing on aggression; the smaller the tank, the more likely.

We have fish profiles here, second tab from the left in the blue bar at the top, or you can click on the shaded name of the fish in posts to see its profile. Info in the profiles includes number, minimum tank sizes, behaviours, etc. The Black Skirt Tetra [Black Widow Tetra is another common name and the one used here] is a characins that gets too large to be comfortably housed in a 10g aquarium. A group of 6 or more in a 20g or larger tank would work. If you read the profile, it specifically mentions fin nipping if kept in smaller numbers in smaller tanks.

There are many fish that would suit a 10g, but they are almost all shoaling fish requiring a group, and thus small; either the Betta would eat them or they would nip its fins.

six

Thanks for responding!

I do weekly 25-50% water changes with a vacuum/siphon, so I get a lot of gunk out of the pebbles. Sometimes it is every other week, however. I do not put any salt in the water. I have tried both the Maracyn and Melaflix with and without the carbon filters in, so I'm not entirely sure what I'm doing wrong. When I first got the betta I didn't know much about fish at all and so didn't recognize fin rot when I first saw it... he had it for a while before I started treatment, poor guy.

Thanks for the advice about the tetras. I'll have to take a little while to think about my options.

Calmwaters

Please do post about the fin rot in the betta section they can give you more ideas on how to cure it.

tanker

My bettas are in 20L (approx 5 gallons) tanks and all seem to have plenty of room. Could you make your 5 gallon tank your betta's permanent home, and have tetras in your 10 gallon?