Guppy=neon tetra

[T21MomLove]

My guppy is chasing my tetras around the tank. Two have come up dead with a missing eye. I thought Guppies are peaceful. Why is he doing this? The store thought it had to do with the bright color or that he wants to mate but I am not to sure by the way he chases them. Should I get rid of him?

 

[Khuligirl93]

What size tank are they in and how many do you have of each?

 

[T21MomLove]

2 female betas, 1 guppy, 3 neon tetras now (2 died ), 1 mickey mouse fish. 20 gal tank.

 

[tnfinfan]

Chasing is territorial behavior. Adding decor to break up sight lines can help but it could be that he simply won't be happy in a community tank. Fish are individuals and even a species that is typically peaceful can have aggressive individuals. That said, I'd spend some time observing to be certain he's the culprit because bettas (even females) are the more likely candidates for killing other fish.

 

[Khuligirl93]

Adding a couple female guppies might work to distract him. Granted you might have some baby guppies, but the other fish will probably make short work of them. Although I agree the betas could potentially cause problems and might be the ones picking off their eyes.
Also, once you get the problem that caused your neons to die figured out, increasing the school to 6 or 8 will help them feel more secure and them being a larger group might make the guppy less inclined to chase them.
Also something to consider is that the ones that died could have died from other reasons, and the eyes got picked off by the guppy or betas after they were dead. It's not uncommon for fish to pick at other dead fish.
How long has your tank been set up? Is it cycled? What are your ammonia, nitrite and nitrate levels?