Mosquito and Midge Larvae-More FREE fish food
Probably the easiest cultures to maintain are what comes naturally from the yard during spring through fall seasons in the northwest.
Culturing them is as simple as placing out a bucket of clean water or a tray of clean water and leaving it to sit for a few days. You can use tap water as the chlorine will naturally dissipate with time.
In just a few days you will see tiny black floating bits often at the edge of the container. If you look closely, they look like tiny pieces of charcoal. Those are mosquito egg rafts! Each egg raft looks like a tiny grain of wild rice. The rafts break apart easily. Each raft contains 50-100 eggs.
Photo below is 60X magnification. I have a small clip on magnifier for my phone.
In each raft, there are hundreds of eggs. When they are first laid, the rafts are white. Within about 8-10 hours, they gradually turn darker and then to black. Wait about 24-36 hours (depending on temperature) and they will hatch into the tiniest of wiggling insect larvae. These tiny ones are ideal for feeding fry. They are about twice the size of newly hatched brine shrimp.
In less than 10 days, the larvae grow, eating whatever is in the water: algae, tiny bits of pollen, detritis and even other smaller critters. When they are large enough, they transform into comma-shaped pupae that last about a day before changing into adult mosquitoes. You will find that different types of mosquitoes will grow to different sizes before they metamorphose so there will be smaller pupae and larger pupae.
For our purposes of feeding fish, we want to feed them in their larval stage since the wiggling attracts the attention of the fish. Fish will eat the pupae as well but they may be big enough that smaller fish cannot fit them in their mouths.
Don't be worried if the occasional mosquito hatches out in your home as both parents must eat a meal of flower pollen or nectar before they mate. Only then will the females look for a warm-blooded host to feed from to get protein to lay her eggs to start the cycle again.
I use a fine-meshed net to catch the mosquito larvae and swish the net into some clean water. Use a container that the net fits into. A turkey baster can also be used to target larger larvae one at a time if you are patient. This leaves the rest to grow.
Another freebie insect larva that is common is the blood midge. Often called "blood worms" in the pet trade, these are actually not worms at all. They are the larval stages of a small non-biting midge. Midges are similar to mosquitoes but have more feathery antennae, are usually smaller than mosquitoes and don't bite. They too eat detritis in the larval stage.
They differ from mosquitoes in their larval habits in that they have jelly-like eggs that are attached to anything just a few inches under the water surface.
Those hatch and the tiny larvae build small 3-sided houses from small bits in the water.
They live in these houses, adding onto them as they grow, until they are big enough to take a swim. Then they will wiggle around and settle, eating more debris.
They are called blood worms because as they get larger the red color gets darker. The red color comes from the hemoglobin. This hemoglobin allows them to live in lower oxygen levels.
Blood midge larva are a favorite of many fish. I use a turkey baster to suck them out of the water and into a small container that I can take inside to feed to my fish. A fine net can be used too but some of the debris from their houses tends to get trapped in the net.
Both Mosquito and Midge larvae and pupae can be frozen. If you find an overabundance that you can't use, place 20 or more in each pocket of an ice cube tray with as little water as possible and freeze them. Pop the ice out and place in a container in the freezer for feeding during the off season.
When the container looks too gross for you to handle, just dump it out, swish some clean water around and refill with clean water. Wait a few days and you will have a clean supply food!
A shallow tub works just as well as a deeper tub and is actually easier to check at a glance. Smaller tubs heat up faster than larger ones and the mosquito larvae grow faster.
No More Mosquitoes
If you decide you don't want any more mosquito larvae, simply empty the tubs, turn them upside down and let them dry out.
Or, if you are collecting from a still bird bath or other similar water feature, add a drop or two of bio-digradable dish detergent in the water. This reduces the surface film on the water and the mosquitoes cannot stand on it to lay eggs. Of course, you don't need to use this on a water fountain as mosquitoes don't generally lay eggs in moving water. The moving water will also make bubbles!
Embrace nature's bounty!