Are these flies okay for fish?

Are Drosophila fruit flies suitable for feeding to community fish such as rasboras, gouramis and barbs?

NEALE REPLIES: Fruit flies are an entirely natural and nutritious addition to the diet of your fish. They’re a great food for all sorts of fish, and among the best choice for surface-feeders like hatchetfish, danios, and halfbeaks. Other fish will certainly take them as well, but that depends on how easily they are adapted to reach the surface and snatch food away. Some gourami species will feed from the surface quite readily, and danios and minnows will snap at anything that lands on the surface of the water, much like salmon and trout, albeit at a smaller scale. But fruit flies don’t sink, and midwater fish, such as harlequin rasboras, might not even notice they’re there. So, if you have a mixed community, fruit flies wouldn’t really add much to the nutritional intake of fish such as these. Either way, I’d not recommend feeding fruit flies on their own as a diet, but alongside good quality flake and pellets.

One of the nice things about fruit flies is that you can get wingless forms that won’t escape from the tank and colonise your house. They are also very convenient to rear. Buy a couple of tubs of larvae, called cultures, put them somewhere warm, and within a week or so there will be enough offspring produced to feed your fish for months. So long as you leave some adults in the container, they’ll lay more eggs, and the cycle repeats. You can also buy tubs of live flies rather than cultures, but since the flies are short-lived, such tubs will only last a few days.