Bully?

[bex1]

Hey so i have 1 Boesmanni Rainbow fish now as the other one i added last week died suddenly yesterday. i think the rainbow i have left is a female, but could be a young male, can these fish be aggressive because i have added 2 more female boesmanni's at different times to my tank to give the one i have some company and both times they have died suddenly within a week?? none of my other fish are ill etc and all the stats are fine! i did notice that both times the dead female rainbow had a bit of tail missing!
i also noticed that the boesmanni i already have was always flaring its fins at the new one, i thought these fish were peacfull? do you think that my original boesmani is a bully and picks on the new ones or could it be someone else (look at sig).
i dont know what to do now as i thought boesmanni like to live in groups but both times i have added another female they have died!
any ideas on whats going on??
thanks (sorry for long post!)
x x x

 

[bex1]

Any Ideas??
thanks x x

 

[TammyLiz]

It wouldn't be any of the others...it would have to be the rainbow. I can't be much help other than that because I don't have direct experience with rainbows (wish I did). I know with barbs it calms them down when you add multiple females but each fish is an individual and I do know that from direct experience! They don't always do what you would expect.

Rainbows are supposed to be schooling species, though. Have you tried adding more than two additional? If I were you my next move would be to get a school of 6 or 8 going, with only one or two males.

About sexing them, it can be hard to tell when they're young. It could be that you have a young male and are adding other young males, misidentifying them as females. Which would explain the aggression. If you're going by color alone, this is an easy mistake. Sometimes the males that are not dominant have washed out colors just because they know they're not at the top of the pecking order. And their body shape probably won't be much different between the sexes until they're older.

Another possiblity. Have you watched them, and seen them picking on each other? Or is there are chance that you're having a parasite or other problem in your tank that is killing the newcomers? Some issues do kill over night.

 

[bex1]

hey thanks for your comments.
i cant really fit anymore than 2 extra rainbows as i'll be over stocked!
i didnt see them picking on each other but they were flaring there fins at each other.
dont think there is a parasite etc in the tank as i added 3 platys at the same time as adding the rainbow fish last week and there all fine!
anyway thanks for your help, any other ideas etc welcome,
thanks x x x

 

[Parin]

M. boesemani can definitely be aggressive. Especially if they have been alone for a while. But you've said it yourself, they like to live in groups. A pair however, is not a group.

If you can't add more than one additional rainbow, then perhaps you should consider one of the following options:

- Donate your single female to someone who can keep her with a group of other M. boesemani.
- Donate/sell your other fish, so that you'll have room for additonal M. boesemani.


However, I must say, that rainbows are often weak in the first weeks after adding them to a tank. When I get a group of rainbows, of let's say 5 or 6, there's sometimes one death within the first week and all the others are fine. Not always, but sometimes. It's like some can't handle the stress as well as others can.

Now in your situation, your new fish is constantly harrassed by your old fish. So she doesn't have time to "unstress". And that's your problem I'm thinking.

 

[TammyLiz]

Moving the decorations around can be helpful when adding new fish, so that the original ones hopefully feel like they are in a different area as well. Although I think it is more for the territory thing than the aggression, it might be worth a try. If you have another tank to move some of your other stock into so you can fit more rainbows, that'd be great. Or if you have another tank to move your lone rainbow into for a week or so while you let some newcomers get settled into the main tank that'd probably help, too.