Vinegar eels are a extremely tiny aquatic nematode (about the size of microworms or smaller), really a worm, not an eel. They are found naturally appearing in vats of vinegar. They make excellent food for fry of nearly all species of aquarium fish. Their advantages over microworms is that they are slightly smaller and they live longer in the aquarium. Their disadvantage is the somewhat more complicated harvesting methods that are required.
To start a culture of vinegar eels will require the following:
A quart or larger jar or bottle
Apple Cider Vinegar
A small piece of apple
A cloth cover for the jar, or a sponge type stopper for a bottle
A starter culture
To start a culture dilute your apple cider vinegar half and half with water, (1 part vinegar to 3 parts water will also work), add a small slice of fresh apple, add the starter culture and put all of this in a clean bottle or jar. Cover the jar with a cloth cover , a sponge stopper or even a paper towel. Don’t use metal lids as it is reported to kill the culture.
Store this culture in a dark place and wait a couple of weeks. You should be able to hold a magnifying glass up to the culture jar and see millions of vinegar eels swimming around in the jar. That’s it! All you need to do now is look at the culture from time to time to make sure it is still “cooking”. If you notice a drop in production you can add a little vinegar, a small piece of apple or possibly even start a subculture.
To harvest the eels I usually use a turkey baster to slurp a portion of the eel culture and squirt it into a coffee filter that is placed over a cup or small jar. Be sure to save the drainage to add back to the culture as it probably contains a lot of baby eels. Once the vinegar mixture drains I will rinse the filter once or twice with clean water to get rid of the vinegar residue, all you have to do is squirt some water in the filter just like you did with the culture mixture. When it’s done draining you can now invert the filter into a small container of water and swish it around good to loosen the eels. Now you can use a dropper or baster to dispenece the eels from the water into your fry tanks.
Note: Small adult fish such as Guppies, Tetras and White Clouds love these tiny eels also.
A new harvesting method was recently posted on killietalk.
Pour a portion of your vinegar eel culture into a small “long neck” bottle. Fill up to the point where the neck starts. Place a plug of clean filter floss into the neck and then fill the rest of the way to the top with clean fresh water. A few hours later many eels will have migrated thru the floss into the freshwater and can be easily harvested. Seems the vinegar and water stay separated so you don’t have to worry about getting vinegar into your fry tanks. When you are through return the culture mixture back to the main jar. Now that sounds a lot more simple.