I like the banded killifish over the gambusia. Banded killifish aren't quite as tolerant to predation, but hold up far better than FHM. They like gambusia are top water oriented and tend to feed in the upper water column. They also reach a good forage size, mine average 3"-4" in size with some topping 5". They are fractional spawners, meaning they spread their spawning out over the entire warm months rather than one big bang in the spring. They will leap out of the water, take to extreme shallows and when really cornered, actually dive into muddy or soft sand substrate to escape. If you are in the eastern 2/3's or so of NC where your pond is in an Atlantic drainage, I would recommend them.
My experience with gambusia is they are extremely aggressive. Out competing other small species, but only reach about an 1.5" in size making them less valuable as forage. Although gambusia, both the western and eastern species are native to many areas, they are also not native to many areas. If introduced to the wrong area, they can have devastating affects on native fishes there.
