Need HELP!!!!

[shmeLLyfisch]

I have a 20g Nano reef tank. 6 weeks old. Cycled for a month. 2 water changes since. 4 damsels, 2 feather dusters, 1 sebae, 2 clowns and some zoanthids. I used 40lbs of LS and 30lbs of LR. I woke up this morning and my fish were gasping for air at the top of the tank. A few died before I could get to them. I tested my water levels:
PH- 8.0 Ammonia- 0 Nitrite- 0 Nitrate- 0 I would go to my LFS but he gives me the feeling that he just wants to sell and doesnt care. Please any suggestions would be greatly appreciated.

[Loverotties]

Do you us a protein skimmer?Also do you have any type of film on the top of water?

[Aceswife]

When was your last water change? Are your corals/inverts affected at all, or just your fish?

[shmeLLyfisch]

just my fish. 1 died and the other two are bagged up in fresh water. I picked up a poly filter and added a bubbler. Hopefully this works.

[Loverotties]

Can't help if you don't answer my question.If you have a film on top of water ,there is no oxegyn be exchanging.you should do a water change now and make shure it's the same temp as in the tank.