Apologies that I am unclear as to what you are suggesting to
@FishOwner101 ? I like guppies and I like endlers but I've heard that they can be aggressive. I'm always out in the lookout for information on the topic.
Are you suggesting that he mixes males and females and that will fix the aggression?
Or put them, the males and females together in the breeder box together?
Or are you suggesting that he get more and then just isolate the one aggressive fish in the breeder box?
I know aggression between fish can be a natural activity for breeding, establishing territory, etc., it's just not something I want to have as part of my fish keeping experience.
I realize this may limit me. In fact it already has as I was hesitant to put even two species together! Now I want to add something else and it will probably take me a year to until I feel satisfied that it will be okay to try something. Maybe not?
Now I'm just rambling...
I've heard that cichlids can be very aggressive and there are many people that keep those but I imagine that takes a lot of knowledge and probably a few losses along the way. Or little knowledge and many losses.
I'll just keep admiring them since I don't have any knowledge about them.
I'm probably going to pass on guppies as well!
I do agree with what
@Bettaguy08 wrote about the temperament of the individual fish involved and I understand there are always exceptions.
Also about stress as a factor.
(I don't remember what member it was that explained that fish give off chemicals when they're stressed out or when they're unhappy and then that could affect the other fish). After having internalized that information, I can't help but think of what that fish is going through to be exhibiting that kind of biting and killing behavior. It's beyond normal.
@FishOwner101
It sounds to me like the internet gave you pretty good advice, return your guppy or get some females. If you get females and they survive the aggression you will start getting a lot of guppies.
Maybe take it back and if you really want guppies do some research to find out what it takes to keep them peacefully. At least within the standards of the natural world they come from.
Finally, I am very, truly sorry about your fish.
..........