Hey,

Well I recently have taken over maitenance and what not for my/my bros tank (he went to college).

Finally I got some new sceneray, fish, and cleaned the tank...hadnt been cleaned for awhile.

Anywas, today is the second day that I've had these new fish (2 of which are guppies, females i believe).

Just today I noticed that one of the guppies was hiding on the bottom of the tank next to a plant.....Then I realized she had nip marks on her back Fin (anal fin?). She hides now.....either in the rock i have, or just somewhere low..It is making me mad, cause whenever i put some food in, and if the one who has these marks goes to try to get some food, the other one will come and scare her away...im guessing that this other guppie is the attacker.

I put more food in to hope that some will get to this injured/atttacked one....i'm worried..

What should i do to stop this aggression, and should i do anything to make sure this other guppie heals?


EDIT:
Sitting here obvserving more....it looks like all my fish are going after this guppy lol.....well. not all, but my lemon tetra definently did, the other femal guppie seems to be just following this guppie at times, but i havent seen any actual bites, besides the aggression over food.

IDK...also, my zebra danio (kinda crazy guy....always going wacko over nothing) sometimes appears to be chasing the guppie...but idk

Well, i think you will have to remove the guppy pronto and keep it in a seperate tank. Once she heals, try letting her rejoin her old tank mates. If it still continues then she has to be separated for good.
MOst of the fish are attacking her because they know that she is weak and cant fight back. Just like humans , we like to pick on the weaklings, fish do the same thing as well.
Hope this helped

The fishes must be compatable. Fast fish with other fast fish. Slow with slow. You get the picture.

I highly doubt that you are able to improve the situation even with the most drastic move ... which is ... remove all fish except the guppy, and allow the guppy to establish its terratory for a couple of days. Slowly add the most non-aggressive, slow fish one by one. By the time you add the most aggressive fish, it will be on the defensive, rather than offensive, as it has no more territory to acquire ... but after a few days, I suspect that the aggressive will bully the guppy again!!!

Just seperate them!!!