Am I doing something wrong?

[Fyfer8]

I just recently purchased a pair of true percula clownfish about a week ago. 2 days ago, I noticed a cloudy haze over the female's body and immediately called the LFS where i got them. She believed it to be a bacterial infection, and after some research on the behavior and physical attributes my fish was showing I agreed (along with the body haze, my fish didnt ever seem to eat). I went to her store and purchased a product called RALLY to put into my quarantine tank w the fish as directed. Later that night, my percula's black coloring had almost gone light gray but i thought maybe the rally was attacking the bacteria. When i woke up the next morning, my new fish was dead. Needless to say i was pretty sad that I couldnt nurse it back to health. When examining the smaller male percula next that morning, I am now seeing that one of his eyes is buldging out like its swollen all around. Is this my fault or is it possible these fish sick before i got them?

Background - Ive had my tank for almost 3 months now and had damsels do well in it for a while before deciding to get some fish that were more appealing to me. I picked up a mandarin dragonet, who is doing wonderfully. I've had her for about 3 weeks and she is eating the copepods in my tank or even the small pieces of mysis shrimp.

My water levels have been great, minus the tempurture changes in the last week due to weather. My tank went from 78 to 80-81 the last couple days because its been so hot. My nitrate levels were the only chemical a little off because the first time I fed them, I put too much food in the aquarium. My nitrate went up and i had A LITTLE bit of algae growth one day. I cleaned it off the glass and it never grew back.

Salinity - 1.024
Alkalinity - 8dkh
pH - 8.0 (i recently bought a Alk buffer that helps raise pH as well)
Calcium - 500
Phosphate - 0
When i will get home i will take another nitrate reading to make sure its not out of whack.
I do weekly water changes about 15%

What could have brough about these infections? I know mandarin dragonet's are very disease resistant acording to books so i can't rule out that something bad is floating aruond in my water. Please help!

 

[Fyfer8]

Also, the store picked up those fish that day. So, maybe I learned to never go on days that they stock their fish

 

[NYCBOB]

u said ur damsel was doing great, but the newly acquired clownfish didnt. was the damsel picking on the new comers? why did u treat the clownfish with rally so fast? new fish that arrived in a lfs shouldnt be bought for at least 3-5 days.

 

[Jeff000]

Marine Velvet? the fish could have brought it in on their own and the stress of the move just let the problem get ahead of their immune system.

 

[Gangrene]

I've learned not to buy brand new fish, to the store, as well. I only buy them if they have been there for 1-2 weeks without a problem.

 

[Fyfer8]

I removed the damsels before adding any others to avoid them tormenting the new fish. I had noticed the female hadnt eaten almost at all for the couple days i had her and now the male hasnt been eating either. The cloudy haze was literally covering the upper half of her body and she was breathing very hard with her mouth and gills. Her gills also looked swollen like they werent working properly. It wasnt fun to see in my tank. I do realize moving her to the other tank could have been bad judgement , but im new and it was suggested by the store manager. The first 2 days they were swimming around great but slowed down a lot as time went on. Any suggestions for the other clownfish?

 

[Fyfer8]

Is it bad manners to ask the store for compensation? Or is that common? Is there something bad in my water?