Grindal Worms

Grindal worms are a tiny relative of the common earthworm. Much larger than microworms but only a fourth the size of the harder to keep Whiteworms. Grindals are about half an inch long and as big around as a piece of thread.

They make excellent live food for growing fry and conditioning breeder adults of smaller species such as Guppies, Tetras, Danios and Killifish. They are also greedily eaten by even bigger fish. All fish benefit from some live food in their diet. Grindals live and reproduce well at normal household temperatures, take up very little space and are easy to culture.

Culturing Grindal Worms

An active grindal worm culture
The worms surround a splotch of food
Toothpick for size comparison
Materials Needed
Culture Box – small plastic container with lid, such as a cleaned margarine tub.
Potting soil, enough to fill the container to a depth of about one inch.
Pablum or baby cereal – For worm food
Spray mister bottle – To keep the culture moist
A 2 inch square piece of plastic such as a piece of a fish bag – For harvesting the worms
A Grindal Worm Starter Culture

Starting A Culture
Put up to an inch of potting soil into your culture box, give it a good squirting with your mister, wet it to about the same moisture content as freshly turned dirt. Punch a few small holes in the lid for ventilation. Add your starter culture.

Feed the worms about a half teaspoon daily of the baby cereal, increase this amount as the culture grows, but try not to overfeed (leftover food will spoil and fungus) give it another squirt of water to moisten the cereal. As you feed the worms, gradually spread the food out into a larger area of the culture as it grows.

When the culture is very heavily populated with worms you can start harvesting (usually after about 2 weeks). Harvest by wetting a small piece of plastic and sprinkling some of the worm food on it, the next day the plastic square should be covered with worms, you can then dip this into a cup of water, the worms will fall into the cup and can be fed to your fish. You can use a turkey baster or an eye dropper to dispense the worms.

Grindal worm cultures last for a long time and don’t usually need to be re-cultured until the potting soil has soured or production has trailed off. When it’s time to re-culture just harvest a few worm and repeat the above steps.

Grindal Culture, note worms on grid.
Grindal Culture, note the worms clinging to the grid.Update
I’m now handling the grindal worm cultures in a new and much more productive way. First, no more potting soil or peat moss, now Im using coconut fiber. The coconut fiber is less acidic and is much preferred by the worms. Also since the coconut fiber lasts longer without going bad I’m now feeding the worms fish flake food, specifically color food, instead of the less nutritional cereal based foods. This in turn gives the fish a more nutritious meal with the worms. Notice also in this picture the small piece of grid. Thats cut from a large “needle point” matt that you can get at any Walmart or crafts store.

The harvesting method now is to dip the plastic grid into a cup of water, this makes the clinging worms fall off and wets the grid. Now I sprinkle the wet grid with the food and put it back on top of the fiber. No other water or food needs to be added. I can now go around to the fish tanks and dispense the worms to the fish.

Easier, faster and much more productive. Image