jlk
Aquarium Advice Addict
Using the prior filter media is risk if you do not know what happened to the fish. If they were healthy, no problem. If they all died of an unknown disease, I would be sterilizing everything.
In respect to the black mark, it just looks like a bit of slime coat damage and it will heal on its own. If it changes or spreads, please let us know!
In respect to the black mark, it just looks like a bit of slime coat damage and it will heal on its own. If it changes or spreads, please let us know!