I have a Royal Pleco in with an Oscar I've been treating for HITH with Fishzole. Water parameters are fine and the Royal has been doing fine for the three weeks that I've had him. He's been munching on the driftwood that is in the tank eveytime I see him. I noticed that today he is lathargic and his eyes are sunken in and he is laying on his side at the bottom of the tank.