identify this fish for me please!

[Madratlady]

I bought a load of guppies from a local shop today and this fish was with them. Is it a guppy? It's fins look different.

Looks like a panchax maybe?

I think you're right.

So, I'm finding a lot of conflicting information online, can I keep him or will he eat the neon tetras? He's kind of cute, he has a smiley mouth.

I don't know much about them tbh. There is a possibility that it'll grow big enough to eat the neons so if you're worried then I would probably rehome it. How big is it now?

The smiley mouth is cute Fish that have mouths like that tend to be predators that snatch insects from the surface of the water, so they have upturned mouths. It'll mostly stick near the surface of the water (make sure it can't jump out!), so if it's well-fed then it's unlikely to deliberately go after the neons and it's unlikely that a neon will swim right past its face.... but there's always that chance that a neon could get eaten.

You could always set up another aquarium

It looks like they are known for eating smaller neons and will definitely scoff any guppy fry so I think he's going to have to go back to the shop.

Don't encourage me to set up another tank! I have a 125l one in the garage that's being sold tomorrow, I kind of want to keep it as either a marine tank or for a small group of discus, but I have a 240l and a nano tank, 3 is too many. And I haven't got the space really.