Very pale clown

[Sammeyrama]

I have two phantom clowns and a RBTA that have had issues coexisting. The larger clown will relentlessly pick on the smaller one of it gets anywhere near the nem. I've noticed he's been looking a little stressed (not as brightly colored, top fin slightly ragged and a little pale). This morning I turned on the lights and he was so pale I thought he was dead and his lips are white. I turned up the oxygen in the tank and added some probiotics to the tank. Any idea what's doing this to him? Is it an illness or the other clown?

 

[ThRoewer]

My first guess would be stress by being constantly attacked. You should separate them either by putting one into a breeder or better acclimatization box or ideally putting the chased one into a different tank for recovery and observation.