Arrr yes the "Gambusia Affinis". From the Poecilidae family.They also come in a spotted form. They make great food for cichlids. They love mossies larve but they compete with native fish for food. keep them or dont keep them? I think that as long as they are controled then they should be fine, as long as they are kept out of our water ways , where they can compete with our native fish.