Hi all. I need advice. I have a pygmy Cory that seems to have fallen ill. It's lethargic - not sure if it's fin rot / bacterial, but I've tried treating with half dose of Seachem Polyguard (as instructed), bearing in mind that there are shrimp and this is not ideal for them. I've now removed this cory and put it in a quarantine tank. What I'm trying to do, however, is remove the underlying cause. In terms of water quality and parameters:
pH: 6.8
Nitrates: < 10
Hardness: Water is on the soft side, but within allotted range on strips
Nitrite: 0ppm
Ammonia: 0ppm
Water Temperature: 25 degrees Celsius
I'm not sure of buffering capacity, but my ph doesn't seem to swing all that much before / after water changes.
Aquarium setup: 8l/m (4x2) 2 sponge filters on a 60l/15gallon tank,
Stocking:
8 Eyespot Rasboras,
10 pygmy corydoras (8 of which are juvenile)
40 Neocaridina shrimp (Various ages)
1 Female Guppy
2x Nerite snails
Few bladder and other pond snails
Water change schedule: weekly 25% water change
I suspect it might be in the substrate, or below it that might have gotten bad. I'm not sure. I'm using Prodibio Aquasoil, but do have some of the old gravel that was washed below it for some height. Is this where I'm going wrong? Any suggestions would be appreciated.