Vinegar Eels are most commonly known as a very easy to culture live food in the aquarium hobby. As the name suggests, they can live in vinegar- but they are not “eels” and are actually tiny nematode worms. They are most suited as a starter food for feeding young and tiny fish that are too small to feed on microworms and newly hatched baby brine shrimp, which are similar in size.

Species: Panagrellus spp
Common name: Vinegar Eel
Group: Nematodes
Size: 1mm
Lifespan: 10 months (as individuals)
Diet: Bacteria and yeast in the vinegar.
Appearance: Very tiny white worms. Can be seen by naked eye if viewed in the culture with a flashlight.

Housing

Our recommended size: Jars/bottles/cups with a lid, with holes or loosely fitting lid for air. Larger containers 500ml+ recommended, as vinegar eels do not culture as dense populations.
Temperature: Room temperature. Avoid temperatures above 28C.
Substrate: Diluted apple cider vinegar and dechlorinated water.
Maintenance:

• Start a culture by pouring a 2:1 ratio of apple cider vinegar and dechlorinated water into a jar/bottle/cup. 
• Rinse and chop up a slice of apple and place into the culture. 
• Seed the culture by adding vinegar eels from an established culture and place a lid on top of the culture.
• Typically, no maintenance is needed to culture vinegar eels for many months. If the culture becomes very cloudy, or it has been six months the culture can be split and refreshed to make two new cultures. This is done by pouring one half of the culture into a new jar and refilling the split cultures with new 2:1 apple cider vinegar and water mix. 
• If you are experiencing film developing on top of the vinegar, stir up the culture to break it up or physically remove the film if it is getting thick. This will not affect the vinegar eels unless left to build up.

Harvesting and Using Vinegar Eels

Vinegar eels are usually ready to harvest 2-4 weeks after initial set up.

• To harvest, use a pipette to suck up vinegar eels from near the surface of the vinegar. The worms typically stay near the surface unless the culture has been stirred up.
• The vinegar eels should be strained and rinsed through a coffee filter with water to get rid of any excess vinegar, which could affect aquarium pH if fed directly.
• Invert the coffee filter in the aquarium, or use a pipette and water flushing to suck up the worms to feed directly in the aquarium.

Vinegar Eels can live for an extended period of time, swimming about in the aquarium until eaten. These worms are considered a starter or transition food for tiny fry, it is not recommended to only feed vinegar eels to fry as they grow. It is always better to provide a variety of live food for the health of the fish.