Clownfish problem

So I introduced one clownfish to my tank and waited a few days since its a new tank. I introduced my second clown and all was well.
They swam together, it was eating, all was good for 3 days.

Did my weekly water change 3 days after i got the second clown and my first clown started getting aggressive with the new one

Since that day the second clown won't eat, stays away from the other clown, kinda breathing a little more rapidly and its poop looks stringy and white. There is no slime on his body, no white spots so I know its not brook or ich

I'm not sure if the fish is sick or just stressed? I read that stressed out clowns will not eat and then their poop changes

The first clown is fine. Its swimming, eating(little piggy actually), poop is normal. He keeps swimming to the other clown but the other one just moved away or stays low

Water tested
ammonia 0
nitrite 0
ph 8.2
phos 0
nitrates less than 5
sg 1.024
temp 79

 

If the clowns are not both females, then one is perhaps sick. I have had new clowns go for days without me witnessing them eat.

Looks for signs of the usual suspects, Cryptocaryon irritans, Brooklynella......

Research the clown fish hierarchy if you have not, determination of females and males.

 

are they the same species and what species are they, same size? if so then they are probably both male and one is becoming dominant and will eventually turn into a female (will become considerably larger too).... personally i would not worry to much, but keep an eye on them. stringy poo is not a good sign.... it is best to introoduce them at the same time but whats done is done, also 3 days isnt that long so territory is not utterly defined yet (my scientific unbacked opinion). how big of a system are we talkingh about too?

 

Example of a male and female true percula. Once upon a time they were both male.

sorry for the blurr they wont sit still :s

 

Before purchasing a few ppl recommended getting one at a time due to the tank being new, I waited only a few days. Its 15g system.

They are both ocelleris, one orange and one black and white, roughly same size. Normally I would go one larger than the other but it was suggested keeping them at similar size if not inteoducing at the same time.
I'm not too worried about the aggression because it really isn't that bad, I've seen worse. More the fact that the fish is not doing so well...but I guess its nature.

I love your clowns good luck ever getting a clear pic of them

 

Just checked, definitely neither of those diseases.

"He" has nothing on his body, actually his scales are great, no slime, no dusting, no ich, no belly bloat, nothing wrong with eyes.