Rainbow fish concern

[Martyn87]

Hi Everyone, I have 350l tank that’s 5ft wide. It’s now home to 7 baseman’s rainbow fish, there still young and are starting to colour up. I have brought 2 females and a male to start with attached is a pic of the big male. Then I recently brought another male and what I thought were three females. I’m having concerns with the new group and the new male is bossing what must be a juvenile male he has very little colour at the moment but the new fish have only been in the tank 3 days so I presume they’re jostling for position.

Yesterday they locked lips and there was a lot of aggressive nipping, I nearly split them up but turning the filter to max seemed to settle them. I’ve never had aggression between fish before, if it occurs again, which one should I separate and when? Do I introduce it back into the tank?

I’m going for 9 bosemans total and 3 male, 6 female. Should I wait to introduce the final male or just get it in now so they all grow together?

 

[Colin_T]

If you keep rainbowfish, you want to keep the males in even numbers (2 males, 4 males, 6 males, etc). You also want them all to be the same size otherwise the bigger males will bully the smaller ones.

Having 3 males of different sizes is going to cause problems.

I need pictures and a video of the fish to say which one/s to move but generally you move the biggest male out for a couple of weeks and let the smaller ones settle in. Then try introducing the big male.