How to Culture Vinegar Eels For Fish Fry

How to Culture Vinegar Eels for Fish Fry

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 easy to cultivate and is great for raising babies, until they are old enough to eat baby salt shrimp.

What are Vinegar Eels and How Do They Work?

Vinegar Eels are harmless white roundworms and nematodes. They feed on the microorganisms that are commonly found in vinegar or fermented fluids. 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. They are commonly fed to newborn betta fishes, killifishes, rainbowfishes, and other fry who require tiny food items smaller than baby brine shrimps (which hatch at 450 microns).

Vinegar eels are great 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 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. The following materials are required:

– 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. Allow air to escape from the tops of the containers.

1. Cover the container with a sheet made of paper towel. Secure it with a rubberband. This allows the vinegar eels to breathe while preventing pests from entering. Keep the containers at room temperatures in a cabinet, or on a shelf that doesn’t get direct sunlight.

The wine bottle can be used to easily harvest vinegar eels. In case the wine bottle is damaged, the larger container can be used as a backup culture. You can leave backup cultures alone for up to a year without feeding them. 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. Leave the wine bottle alone for two to four weeks so that the vinegar eel population grows large enough for you to start feeding the fry. 2. When you are ready for harvesting, insert a wad if filter floss into the neck. The floss should be soaked in vinegar.

1. Gently pour a small amount of dechlorinated, tap water into the neck.

1. Wait 8 to 24 hours later, and the vinegar eels will travel through the filter floss into the fresh water to get oxygen.

1. You can remove some vinegar eels with a pipette and then feed them to your fish fry.

This method can be used to feed your fish babies for several days, or even a week. However, eventually, the culture will begin to decline. 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 Do I Maintain the Vinegar Eel Culture?

The apple pieces begin to fall apart around six months. You may also notice that the culture becomes cloudier. That means it’s time to start a new culture. Get a new container, and pour in some of the old culture. Fill the remainder of the container with apple slices, and a mixture of apple cider vinegar and dechlorinated waters. Your new culture should be ready to harvest again in two to four weeks.

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