Guppy Fry Behavior Question
I acquired some guppy fry about 2 months ago from a coworker's daughter (she bought guppies without being aware that they are prolific breeders, haha), and now they are almost adults. Maybe about another month or so until they are mature, so right now they are "teenage" fish.
I ended up lucking out and I have one male and two females (all siblings) but the male is doing something odd and I don't know if it is an indication that there is something wrong with the female, or if the male just has a strange behavior.
So, for the last month or so, since the male started getting colors, he has been harassing the older female, by coming up behind her and nipping at her anal region any time she starts to poop. He doesn't do this to the younger female, only the older one.
It is was an obsession with eating poop, then shouldn't he be doing that to the other female as well?
So, since it is just one of the two females, I'm wondering if there isn't something odd with her. Maybe she is constipated or something and he is trying to help her? She is very round, about double what the other female is after they've eaten, and I've looked for a gravid spot, but I can't see one, so I'm doubtful about whether or not she is pregnant.
Has anyone else observed this behavior in their guppies? If so, do you know what causes it?