For the last day or two, my Ranchu Pierre has been very mopey. Sitting on the bottom mostly. When I tap on the glass by him, he sort of flips his fins around obligingly. He didn't eat today but he got up to eat yesterday and the day before.
The night before last I had him in a little gallon tub with some salt.
The problem must be the new fish I added a week ago. I got three Bosemani's rainbows, six platys, and a gourami. Everyone gets along fine and looks healthy, except Pierre. And no, I have no way of quarantining them, but for the record, they come from an LFS that will not sell you sick fish on purpose, they go out of their way to quarantine new shipments for at least a month and then make sure to get only healthy ones.
Tank is 40 gallons breeder sized, been running since Christmas. Has a heater and is about 74 F. Has an external canister filter. I change out about seven gallons once a week. In addition to the new fish, there are 2 BN plecos, 2 cory cats, 2 rasboras, and a danio. And plants (one of which has a bacterial problem - might there be a connection even though that's been an ongoing thing?). Just use dechlorinator and the occasional plant food additive. No medications.
Why the lethargy? Should I separate him again? Help!