These are wingless fruit flies (Drosophila melanogaster). I previously had the flightless (but winged) version. The wingless are easier to handle and seem more productive. This is just a starter culture. You will want to get fly media which can be purchased or mixed up from ingredients you probably already have in your kitchen. There are many recipes you can find. I'll give you my recipe which includes the antifungal methylparaben. I bought a pound of that, but use only 1/4 teaspoon per batch, which makes enough for about four cultures. Included here is 5 grams of methylparaben. I don't know how many 1/4 teaspoons that is, but several months worth, at least. The spoon is NOT included because you probably already have one of those in your kitchen too.

All my fish from about 1 inch up are able to eat these and even large fish relish them because they move. You can gut load them should you want to get specific vitamins or medications into a fish.