Boesmani rainbow fish attacking/killing eachother

[Matts90]

Hey I have set up a 90 gallon planted tank and just added some boesmani rainbows (6) and they all been nipping at eachother for a week. I have added aquarium salt to help heal their wounds but it seems to be getting worse.

they have been in the tank for a week now and this morning I noticed one is missing thier side fin ( sorry not sure what its called) and I found one dead in the brush of my plants.

i have been doing research and have never once Read anything about them killing eachother...

I dont know what to do. I only have a 15 gallon tank but that one is full with plants and other fish. I know that they’re schoaling fish and should be kept together but I’m going to have to separate them.

I quess my question is has anyone ever seen this before with boesmani or any rainbows? Or if anyone has any suggestions on what to do? I’m puzzled. Thanks I posted pictures of them

 

[Stephen St.Clair]

It's been many years since I kept Rainbow fish, but don't remember any substantial aggression problems. It's not unusual for male Rainbows to chase & constantly pester females.
Your problem appears quite unusual with no simple solution.
You might try adding more Boesmanis into the group, or another variety of Rainbow fish. You could change things up by adding a completely different group of bigger schooling fish such as Denison or Filament Barbs. Anything that would demote the Boesmanis from the dominant group to a subordinate position.

 

[Matts90]

It's been many years since I kept Rainbow fish, but don't remember any substantial aggression problems. It's not unusual for male Rainbows to chase & constantly pester females.
Your problem appears quite unusual with no simple solution.
You might try adding more Boesmanis into the group, or another variety of Rainbow fish. You could change things up by adding a completely different group of bigger schooling fish such as Denison or Filament Barbs. Anything that would demote the Boesmanis from the dominant group to a subordinate position.

Thanks for the good info, it does seem to be a very unusual situation. I’ll have to try something I’ll look into the barbs. Thanks again

 

[Stephen St.Clair]

I've kept both varieties of the noted Barbs. IMO, much better fish to keep.

 

[twentyleagues]

I tried boesmani rainbows and red irian rainbow years ago and had the same issues. I don't believe it's all that uncommon actually. I believe it's a numbers thing, more the merrier. I had started with 8 boesmani and after they killed each other off to about 3 in a few weeks I traded them in for the reds. I got 10 this time and it started again. I got another 10 which by this time I was at about 6 or 7 left. When I got the new ones I added 12 snake skin barbs and aggression seemed to be lessoned, at least no more rainbow fatalities. I would find a barb that was beat up pretty bad occasionally. Tank was a 125 that used to house mbuna with way less issues. At the time I was maybe 18 so that was a long time ago before internet, so all I had to go on was lfs info or books and magazines. I mostly went on lfs info, sometimes very bad. I've not kept the larger rainbows since. I've had furcata and currently I have 5 celebes rainbows these seem very peaceful and I like their overall shape better also.

 

[Fishnerd360]

I keep 4 rainbows similar to boesmani, but they don’t fight/nip at all. I agree with adding numbers may help, but I wonder if you have more males than females, causing them to fight the other males to get to a female. While I don’t know that this can actually happen/rainbows can pair, 2 of mine seemed to have paired up, both being different colors than the other 2, and hanging out a lot together.

 

[Matts90]

I keep 4 rainbows similar to boesmani, but they don’t fight/nip at all. I agree with adding numbers may help, but I wonder if you have more males than females, causing them to fight the other males to get to a female. While I don’t know that this can actually happen/rainbows can pair, 2 of mine seemed to have paired up, both being different colors than the other 2, and hanging out a lot together.

when I bought the rainbows last week I couldn’t go into the store and look because of COVID so the guy just grabbed em and saidI don’t have time to separate males from females, when I got home I found out that I now have 4 males and 2 females. All the males now have wounds and one I dead. I think it may be a pairing issue where they are fighting for the females