How to Culture Vinegar Eels For Fish Fry


How to Culture Vinegar Eels for Fish Fry

Do you want to get into fish breeding, but don’t know how to feed tiny fry too small to eat regular food? Vinegar eels might be a good choice! This live food is very easy to culture and is perfect for raising babies until they’re big enough to eat baby brine shrimp.

What Are Vinegar Eels?

Vinegar eels are harmless, white roundworms or nematodes that feed on the microorganisms commonly found in vinegar and fermented liquids. They are small and easy to grow, measuring in at 50 microns in size and 1 to 2mm in length. They are often fed to baby brine shrimp, killifish, rainbowfish and other fry that need tiny foods.

Vinegar eels have many other advantages that make them ideal for feeding fish fry. They can survive several days in freshwater unlike micro worms like banana worms. Because they swim in the water column rather than sinking straight to bottom, their wiggling motions encourage babies to eat faster and eat more. Vinegar eels don’t have the same nutritional value as baby brine shrimps (which are born with a rich yolk sac), but they are a good food to feed until fry become large enough for baby brine shrimp.

How do you start a Vinegar Eel Culture.

1. These materials should be collected:

– Starter culture of vinegar eels (from local fish auctions or online sources like – 1 container with a long neck (like a wine bottle) – 1 backup container (like a 2-liter bottle or 1-gallon jug) – Apple cider vinegar (enough to fill half of each container) – 1 apple – Dechlorinated tap water – Filter floss or polyester fiber fill (stuffing for pillows and stuffed animals) – Paper towels – Rubber bands Pipette – Optional: funnel

1. The apple should be cut into small slices so it can pass through the container’s openings.

1. Divide the starter culture of vinegar eel into each container. 2. Fill the rest of the containers with 50% vinegar and 50% dechlorinated tap water, such that the total liquid amount reaches the base of the bottle’s neck. (Leave a little space at the top of the containers for air.)

1. You can cover the container’s openings with a piece of paper towel and secure it with a rubber band. This allows the vinegar-eels to breathe and prevents pests from getting in. Keep the containers at room temperatures in a cabinet, or on a shelf that doesn’t get direct sunlight.

The wine bottle is your primary culture that can be used for easy harvesting of vinegar eels. If the wine bottles are damaged or destroyed, the backup culture is in a larger container. Backup cultures can be left alone for as long as a year or so without needing to be fed. Although the population might be declining, you will still need enough vinegar eels to create a new culture, if necessary.

How do I harvest vinegar eels to feed my fish?

1. Allow the wine to sit for at least two to four more weeks before you start feeding the fry. 2. When you’re ready to harvest, stuff a wad of filter floss into the base of the neck so that part of the floss is soaking in the vinegar.


1. Gently pour a little dechlorinated tap water into the neck of the bottle.

1. Wait for 8 to 24 hours and the vinegar eels can travel through the filter floss to the freshwater to get oxygen.

1. Take some of the vinegar-eels out with a pipette, and give them to your fish fry.

Although you can feed the fish for several days straight, it is not recommended to do so for more than a week. 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.

How can I preserve the Vinegar Eel Culture

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. The rest of the old culture should be poured into a new container. In two to four weeks, your new culture should be ready for harvesting again.

To read more like this, sign up for our newsletter and receive a weekly email containing all our blog posts, videos, live streams, and videos!