It's possible with a large number of species. Although, with some, you really don't want to get your fingers within striking range. Not a problem with this fish.
Golden Wonder Killie
Properly describes as Aplocheilus lineatus by Valenciennes in 1846, the Golden Wonder Killie was originally found in Southern India. Most are now farm or hobbyist raised specimens. A top water dwelling species, the Golden Wonder Killie (sometimes called the Yellow Killie) prefers a planted aquarium with dense vegetation along the fringes. The water parameters are best when slightly acidic and moderately soft. While you can use a fairly small container, be sure to cover the top, as this Killie loves to jump. Males can be rather aggressive and should not be housed with smaller fish. It is an adhesive spawner and will use plants of a provided yarn mop to lay the eggs. The pair will lay a few eggs every day, and you should remove the spawning material after 5 to 7 days to stop the pair as they will become exhausted. The eggs should be removed and kept moist, then placed in a hatching aquarium. They should hatch in 12-15 days and will need to be fed fresh hatched brine shrimp or microworms.
I have a friend who keeps a kiddie pool full of plants and killies. Its nice to sit and watch the killies run the top of the water during feeding time. Cool little fish!
I also have a halfbeak in the tank with it, and it seems like the halfbeak is being a little aggressive, and I was wondering if this is normal cause it hasnt actually bit it. It just opens its mouth and swims at it slowly.