Like the title said my fish are struggling to breathe, and a few of the older ones have died.
I have a 57 gallon, heavily planted(dirt tank) 10 neons, 10 rasbora, 2 large pleco, 3 small algae eaters, 6 oto, 2-betta, 3 tetras, 1-bala shark, 1 dwarf gourami, 20 -ghost shrimp, 3-yoyo loach (4in), 1 clown loach (2in),
The water conditions are:
The tank has been setup since July of 2012.
Here is what I did yesterday:
-Pruned some of the plants
-25% water change (Last water change was Sept of 2011)
-Cleaned the canister filter (same way I always do) replaced the 2 blue/white filter media, lightly rinsed the 2 inch foam filter.
The tank was fine last night, this morning my wife calls to tell me the neon's are swimming funny and at the top of the tank gasping for air. few hours later she calls and says a really old 7-8 yr old white cloud has died, and the bala shark (7-8 yr old) is swimming on its side.
the shrimp are fine, the betas are fine, most of the algee eaters are fine. It seams like most of the older fish, neons, and one Chinese algae eater are struggling.
I left work early to try and figure out what was going on, water seemed good from what I tested except for the nitrates. I added a power head and air pump to get some movement and O2 in the water. With in 10 minutes most of the fish seemed to start to relax a little but are still breathing harder than normal.
The power head is big moving 800 gal/h which is way to much water movement but the fish seem to like it.
Any help or ideas would be great.