Are mosquito fish in the same family as guppy?

My lps had a small male mosquito fish (sure of it, doesn't look the same as my feeder/fancy males - no extra color but nice even black spots in fins) and I am wondering what they are considered. He is about half the size of my fancy male (bulk wise) and about twice the size of my feeder males (which have refused to grow any bigger! they are less than an inch why mr. mosquito is close to over and inch).
I got him as a feeder guppy, but he doesn't look like them enough for him to be a guppy (different body shape, eyes larger, fins more even/rounded).

 

Can you post a picture of the fish? That way we can be certain.

If it is indeed a mosquitofish, then to answer your question, no, mosquitofish and guppies are not in the same genus. Guppies are poecillia sp. whilst mosquitofish are Gambusia affinis.

If you're wondering whether your mosquitofish can breed with your guppies, it is possible for it to happen. Sometimes species can breed outside of there genus, but most of the time it won't happen unless the fish are in an environment with only 1 male mosquitofish and multiple female guppies. I have heard of instances where mosquitofish have successfully bred with guppies to produce healthy offspring.

 

Yes they're both in the family Poeciliidae. Gambusia affinis, G. holbrookI and Heterandria formosa are usually called Mosquito fish, but there are several more species in each genus.

 

I got a few pictures of him, which was easier than some of my other times trying to get pictures of fish.

above

he has sharper scale definition than I have seen in my feeder guppies

his eyes are larger in comparison to his body as well compared to gups

above side, he did very well for his photo shoot and was quickly put back into his tank (male guppies and shrimp) to settle back down from the stress.

 

I wouldn't keep him with your guppys. Mosquito fish are much more aggressive than your guppys.

 

I wouldn't keep him with your guppys. Mosquito fish are much more aggressive than your guppys.

I do not have any slow moving or long finned fish in with him - they are either small enough to evade him or without the long fins that make them slow.