The other day i noticed him rubbing himself on the substrate in the tank, iv noticed this before but only in a much smaller tank and on a fish that had ich. Is it possible the fish just itched or should i treat for ich just to be on the safe side? The other shark i have hasn't been doing at all and neither have none of his other tankmates except the ornate bichir. Ideas, comments, ecommendations. experiences etc. thanks all