territorial guppy??

[Keepers_girl]

Up until today my two female guppies got along very well. Today, however, the full-grown female is chasing away the smaller female whenever she comes near. They used to be inseparable and I don't understand what's going on.....

[aridiar]

Do you have male guppies? The owner of my LFS says that guppies can get aggressive to members of the smae sex if there isn't an even ratio of male to female, unless all of the guppies are of the same sex. So it might be that your larger one is trying to keep the smaller female away from her man

[Keepers_girl]

Actually. it's only the 2 females in the tank at this time....that is why I thought it was strange . We did isolate the larger one about 2 months ago because the male ones in the other tank ate her tail. . We got the smaller female guppy as a companion for her and she seemed to like it until today.

[aridiar]

It could be because of her experience with the other fish. Sometimes being picked on like that makes the fish more aggressive when they are put in a situation when they could be dominant.
How much has the smaller one grown since she was put in? It could be that your bigger one now sees her as a possible threat.

[Keepers_girl]

Update--- originally it was the large female being aggressive, but today the baby chewed off her fin!!(the one on her back). Baby's been moved to another tank, large female is recuperating....