Neon Tetra Disease
 

For the past 2+ weeks, I've scoping up dead fishes every day despite dosing medication and 25% WC every 2 to 3 days.

The neon/cardinal tetras started to die off first. Follow by other fishes.

Below are the casualties
80+ mix of neo and cardinal tetra,
2 oto catfish.
1 algae eater
1 zebra snail
3 yamato shrimps, 3 ghost shrimps.
4 Golden Tetra
2 German Blue Ram
2 Rummy Rose Tetra
2 Serpae tetra
2 Gold White Cloud Mountain Minnow
5 Black diamond tetra
All tiny snails which came with the plants.

Below are the survivors
2 cardinal tetra
1 algae eater
2 Golden Tetra
4 Serpae tetra
4 Rummy Rose Tetra
2 Panda Cory
2 dwarf crayfish
4 Gold White Cloud Mountain Minnow
1 Sterba's corydoras
1 Black diamond tetra

My research points me to Neon Tetra disease. The symptoms fit. An incurable disease.

I suspect the cause of the outbreak is due to the change of biomedia in my canister filter recently. It upset the balance, stressed and weakened the fishes.

The last death was 2 days ago. I would be waiting for another week or two before replenishing my stock. :(