Are you getting into fish breeding but need a way to feed teeny-tiny fry that are too small to eat regular fry food? Try vinegar eels! This live food is very easy to culture and is perfect for raising babies until they’re big enough to eat baby brine shrimp.
Vinegar eels are harmless, white roundworms or nematodes that feed on the microorganisms commonly found in vinegar and fermented liquids. Growing up to 50 microns in diameter and 1 to 2 mm in length, they are one of the smallest and easiest live foods to culture for baby fish. Breeders commonly feed them to newborn betta fish, killifish, rainbowfish, and other fry that require miniscule foods even smaller than baby brine shrimp (which hatch out at 450 microns in size).
Vinegar eels have many other advantages that make them ideal for feeding fish fry. Unlike banana worms and other micro worms, they can survive for several days in fresh water, they swim around in the water column instead of sinking straight to the bottom, and their wiggling motions entice babies to eat more and grow faster. Vinegar eels aren’t necessarily as nutritious as baby brine shrimp (which are born with rich yolk sacs), but they’re an excellent food to feed until the fry have grown large enough to eat baby brine shrimp.
The wine bottle is your primary culture that can be used for easy harvesting of vinegar eels. The larger container is your backup culture in case anything happens to the wine bottle. Backup cultures can be left alone for a year or two without any additional feedings. The population may decline a little, but you should still have enough vinegar eels to start a new culture if needed.
You can use this method to feed for several days in a row, maybe up to a week, but eventually the culture will start to deplete. Therefore, if you have lots of fish babies, prepare several bottles of vinegar eel cultures so that you can rotate between them, giving each bottle four to five days between feedings so that the culture has time to repopulate.
Around the six-month mark, the apple pieces eventually break down, the nutrients are used up, and you may notice the culture is much cloudier than usual. That means it’s time to start a new culture. Get a new container, and pour in some of the old culture. Fill the rest of the new container with apple slices and a fresh mixture of 50% apple cider vinegar and 50% dechlorinated water. In two to four weeks, your new culture should be ready for harvesting again.
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