Likely you've got some Aplocheilus Lineatus. I have two of these guys. I have one that is the more solid gold captive bred coloration and one that has tiger stripes and red/white fin accents of the wild strain.
Most of my LFS's use the common name of "Golden Wonder Killifish." A very hardy and pretty fish, the Golden Wonder are probably the easiest killifish to take care of. They get to be about 3.5" long, will eat pretty much any meaty food or flake, and loooove to jump. So make sure you have a tight lid on your tank.
They are also opportunistic piscivores and have very wide mouths for their size so be careful when keeping them with smaller fish. I got mine when they were very small and raised them on a mixture of frozen bloodworms/brine shrimp and flake foods and they do fine...save for very recently when I accidently killed some of my rasboras with too big a temp differential during a water change. As soon as the rasboras became distressed and started swimming weirdly the killi's punced on them. They left the healthy ones alone, but the weak ones got taken out in seconds.
Overall, though these guys are pretty peacable.