Help! I have mean fish!

Hello. I am a newbie here. I have a bit of a problem. We have a 75 gallon salt water tank. Its been going for about 3 months now. About 2 months ago, we got some damsel fish, just to start out. We started out with 6 of them, 2 blue and 4 black and white. Two died because they got sick. (That was 3 weeks ago.) Anyways, the remaining 4 have gotten along wonderfully, until 2 days ago. The three black and white ones are beating the crap out of my only blue one. He is in rough shape. Right now, I have him in isolation. The only thing that has changed in my tank is the introduction of 6 blue leg hermit crabs 4 days ago. I am having a hard time believing this has anything to do with the sudden attacking of my blue damsel.
What should I do? He is in bad shape, should I flush him and forget about it or is there something I can do?

 

you could wait for him to heal and take him to a fish store. what type of black and white damsels are they 4 stripe or 3 stripe. 4 are pretty mean, and having him be the oddball just means hes more noticable.

 

We aren't adding anything new anytime soon. We will probably keep them until we do. I didn't know that they are such mean fish. We mainly want to have a reef tank, with a couple fish, so I guess when we get better fish, we will have to get rid of the bullies.
Thanks!

 

They are 4 stripe damsels. They are vicious!

 

I had the same problem they all died

 

I put my mean fish in the sump it’s like sending them to timeout =) But in my tank the damsels are the underdogs. Try taking them all out and change a few things in the tank then put them all back at the same time this way they will reestablish territory.

 

Damsels are agressive fish when put in with other damsels. They typically aren't as bad if they are the only damsel in the tank with a few other semi-agressive fish (at least fish that can hold their weight). I'd get rid of your seargant majors, as they are much more agressive than your blue damsel would be on their own. Trying to get rid of them might be a whole other topic however.

 

i don't think he has seargent majors.

he has this

 

Yes, this is the type the 3 bullies are.
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