I was reading about convicts. I read a comment from someone who mention that his/her fish nip on them all the time while tghey clean the tank. Do they bite and if so is it enough to feel? Does it hurt?
I wouldn't put it past them, especially if they're defending eggs/fry. Some NW cichlids are infamous for attacking their owners, some of the larger ones can do some damage (I personally got my thumb bit my my former oscar, it bled but I got over it). Be thankful cons only have small mouths
I know I would hesitate to dangle my fingers in a tank with some of the RD/FH type fish I've seen.