It has long been known among killikeepers that one of the best foods for killifish is mosquito larvae. With the season imminent, it seems a good time for discussion.
Mosquito larvae are generally found in standing, shallow water. Look in out of the way placesponds, puddles, and ditches, deep tire tracks, inside old tires, or in cans and containers left outside. The larvae are small, usually dark colored, “fuzzy” wrigglers that swim with a distinctive abrupt motion. They tend to hang at the surface for long periods, occasionally startling and dashing to the bottom, and can be quickly and easily netted and transferred to a waiting container of water.
The larvae can be fed at any stage of development. The egg rafts (which look like clumps of tiny dark brown cigars floating on the surface) can be dried for later hatching, and both the eggs and the larvae can be frozen for later use.
Don’t feel like tramping through the wilds? You can easily culture your own supply of mosquito larvae. Place a container of old water (the chemistry doesn’t seem to matter) in an out-of-the-way place outside and wait. If they are the water is still, the mosquitoes will find it. You can attract them by “steeping” a handful of fresh grass clippings in the container, or by adding some old leaves or a bit of powdered milk.
Egg rafts will soon appear, followed by larvae.
“I have a few ‘sweater boxes’ outside all year,” says Bob Schraedley. “They’re under a tree and get plenty of leaves dropping into them to create the right environment. I collect daphnia about nine months of the year from these. They freeze up in the fall, but the daphnia always come back right after the thaw. Rather than let the mosquito larvae take over … I collect the egg rafts a couple of times a week. These I put into a one gallon pickle jar and feed very fine flake fish food as they start to hatch.” You can raise them to whatever size you like.
George Davis prefers to “bring the egg rafts inside to grow … in 1/2 gallon apple juice jars full of green water. They are much easier to catch this way, and it avoids other unknown critters. In order to prevent the larvae from maturing … I occasionally ‘vacation’ a few A. linneatus right in the [culture] containers. Clears that problem right up, and returns some fat and happy killis. [However,] I wouldn’t recommend putting your prize killis outside, where kids, cats or raccoons might get to them.”
There Are a Few Cautions, However …
Not all mosquito species bite, but most do. In deference to household peace, be certain to feed only larvae that will be consumed before they have the chance to pupate. The pupae are distinctive: large, round headed, and with a hard shell. “I only feed the pupae to my larger fish and my Nothos, who are always eager and tackle them with gusto,” says Donna Recktenwalt.
— G.C.K.A. Newsletter, June 1998