I've kept ropefish for quite sometime, as a matter of fact when my lfs
has had an issue with one at the store they usually call me. Ropefish are social with each other and prefer other ropefish and that has been my experience until now. I currently have three ropefish. One started to become territorial over a specific cave in the aquarium, but only toward the other ropes (not my angels or GBR's). The aggression slowly spread to the other caves as well (three total). It has now progressed to where the other ropes can go near him anywhere in the tank. He hasn't damaged any of the other ropes, but I don't think they're very happy about him nipping and biting them.
I am currently trying to rehome him, but I am baffled by the behavior and wondered if anyone else has had this issue with a rope. He's well fed, there's plenty of room in the tank, and the water parameters are good. Any thoughts or ideas?