Dwarf Neon Gourami died the other day, I'm confused!

[greenday04]

I have had the 20g for a month now, used BioSpira to cycle, it took 2 weeks do the day. The two gourami's have been in there for 10 days and all of a sudden the other day when I got back from shopping one of them was swimming, actually more like spinning quickly around and around and then sunk to the bottom and died. His stomach was swelled out also. I took the fish back and they gave me my money back. My water tests, both by me and the store, perfectly.

What could have caused this? He was eating fine in the morning.

Also one more question, this is what I have, can I get away w/getting 5 more cardinal tetras and/or a few dwarf cories?

20g
2 dwarf neon gourami (males, I replaced the one that died)
3 gold tailed platy
6 pristella tetras
5 cardinal tetras

Thanks all for the advise

[Harlock]

Well, Several things pop into mindas to what the sick fish could have had. Bloat or dropsy, which are hard to impossible to cure or swim bladder disease brought on by constipation. What kind of diet do your fish get?

Also as far as adding more fish, I feel you're pretty well stocked. 2 rounder bodied 2 inch fish, 3 fish that can get to 2 and a half inches and carry some girth, as well as have fry readily and two schools of tetras. I wouldn't add anything to that mix, personally.