Dead Clown and Snail

[randytester]

Posted in the Newbie section and decided this is more appropriate (sorry I wasnt sure what section)

[hr]
Bought two clown fish about 3 days ago and one just died. He and his friend looked fine a few hours ago, and when i just looked a few minutes ago he was barely swimming and then started floating and gasping for breath. His friend looks like hes doing fine. I noticed that his gills were a bright Pink.
All this is in a 12G Aquapod with about 10lbs LR and 10lbs LS.
I also had a turbo snail die the other day also, but my other 3 are turbos are doing fine. I last performed a water change 2 days go. Acclimated both fish for 3 hours and tested my water just right now they are.
Amonia = 0
Nitrites = 0
Nitrates = ~5-10 (now)
PH = 7.8
SG = 1.025
What am i missing? What do the Bright Pink gills mean? Any help is appreciated

 

[brad pitt]

did u let the water cycle?
how old is the set up?

 

[randytester]

Yes the water cycled for about 3 weeks before i put in my CUC. The setup is about 5 weeks old now. I did add 2lbs of LR last week (im thinking thats why my nitrates were about 20). I'm kinda guessing that the clown just died due to shock? Although the bright pink around the gills made me wonder. Also the fact that one of my turbo snails died the day before made me think it might be more. My 3 other turbos, 5 hermits, and 5 nessarious all seem to be ok as well as the remaining clown and green chromi.