Cory emergency

[toolisj]

20 Gallon tank, 6 tiger barbs, 1 blue dwarf gourami, 4 leopard cories.

Issue: Im not near the tank, so im reporting what i was told. Two cories just sitting on the bottom, one barely moving with beat up fins, the other one laying on its side but more active. Ammonia is zero, PH is 7.6, which i know is high and im working on that. Another thing was apparentely water had been taken out and put back in without dechlorinator, but the other fish all appear fine. Recommended course of action and possible diagnoses? Also, the cories are in a small tank suspended in the large tank to keep the temperature with water being circulated to keep oxygen levels up.

[Lab_Rat]

Sounds like someone(s) beat the cories up pretty badly. My money would be on the tiger barbs, unless your dwarf gourami is particularly aggressive. I would separate out the cories into another tank. Keep their water very clean so they can heal.

[Northernguy]

It could either be the barbs or the gourami that did it.
How did you cycle your tank?
Your ph is fine.I wouldn't touch it if its stable.
What are your ammonia,nitrites and nitrates at?
You can add dechlorinator after the water is in the tank.

[toolisj]

The cycle was long and unfortunate about two years ago, fish cycle. But the tank has been up and running and stable for probably 18 months. Ammonia is zero for sure, but i dont have a test kit for no3 and no4.

[Northernguy]

Those other test kits are just as important as the ammonia test.They both kill fish if they are up to high,especially nitrites.
Try and get an API master test kit.thumbs2: