Firefish and clowns fighting??

[Jcs401]

I just recently bought to fire fish and when I introduce them to the tank left the lights out for 24 hours and now turn the lights on and they seem to be battling what can this be how can it be prevented?

 

[MarinaClown]

I just recently bought to fire fish and when I introduce them to the tank left the lights out for 24 hours and now turn the lights on and they seem to be battling what can this be how can it be prevented?

They are probably going onto Clowns territory and he is protecting it. How big is the tank?