I would like to retract my previous statement.
Seeing the clearer picture: it's a Fundulopanchax Sjoestedti Loe. (98% sure). Sometimes referred to as the Golden Pheasant Panchax, or GF Killifish.
Needs around a 90 litre tank, footprint of at least 90x30cm, and can get over 10cm long.
He should be kept in a trio with two females at least, him and three is better, and if you're used to spawning mops, or want to put the effort in to learn, you may have successful breeding.
I wouldn't keep them with anything smaller than full grown Danio/average full grown guppy. They'll take out anything smaller and will snap up fry and smaller fish with no problem.