I picked these guys up to eat any mosquito larva that show up in my system. Since the water flow is slow here and we have had several cases of West Nile Virus the last couple of years in the area I figured it would be a bad idea to breed mosquitoes. These fish are related to guppies from what the fish guy told me but are more temperature tolerant. They aren't as fancy as guppies but breed the same so I should have more than I know what to do with in a couple of months.