the tank is 55 gallons and its heavily planted.
fish:
2 large angels
5 mixed large barbs
1 pictus catfish
2 flying foxes
1 clown loach
1 yellow lab cichlid
2 neons
2 sailfin mollies
4 platies
1 fire eel
before the "your tank is overstocked" comments come in, i havent had any trouble with this in the past. I have many filters on the tank including
- the largest rena canister filter
1 aquaclear 500
1 whisper 60
1 internal whisper filter
the only reason i need help is because only the platties and mollies are showing signs of stress (gasping at the top for air) all the other fish are doing fine. And i tested the water with aquarium test strips, again i have no ammonia, or nitrites and the ph is at 6.9
ps. the 125 was taken down and some of the fish were spread out into my other tanks, and our tap is run through a reverse osmosis system