Clownfish aggression, more then just dominance assertion

[Yodaman]

So I have a pair of clown fish that I’ve had for a little over 2 years now, and they’ve gone through a few different tank setups and have always done well together.

Recently I setup a 5 gallon and placed them in there, along with half a dozen corals, a couple hermits and a couple snails. The tank has been running with the clowns for about 4 months with normal clown fish behavior, nothing I haven’t seen the almost 2 years prior.

Then suddenly the last couple days I’m noticing the larger (presumably the female) has been going out of her way to chase the smaller one, and even attacking him. To the point his fins are starting to tatter and his colors are going flat. So I removed him from the tank and put him in a 20 gallon I’ve had laying around with nothing else in it. I want to nurse him back to health, then remedy whatever may have been causing the aggression.

So my questions are,

Is there anything I should put in the tank with him while he’s in isolation to make a speedy recovery?

Where should I start checking to reduce the aggression between the two before reintroducing him?

 

[Jekyl]

A 5g tank is much too small for clowns. There isn't likely much you can do with a tank that size. Once healed I'd recommend keeping them in at least the 20g.

 

[Mr. Mojo Rising]

If this isn't solid proof that small tanks have a negative affect on fish then I don't know what is.....

 

[Yodaman]

Well that sounds pretty conclusive on how to move forward. Admittedly, I never did check on how small of a tank I should keep a pair of clowns in

 

[Jekyl]

Well that sounds pretty conclusive on how to move forward. Admittedly, I never did check on how small of a tank I should keep a pair of clowns in

20g is what most dealers recommend

 

[kvansloo]

20g is what most dealers recommend

and to add the second one you would want to add 10-15 gallons so for 2 clowns you should have 30 - 40 gallon tank. Good luck.