Small earthworms about 2 ½ inches long
TOP LIVE BAIT
The fact that worms are one of the top live baits used for fishing should indicate their value as live food for tropical fish! Worms of all sizes are very nutritious and eagerly eaten by most all species of fish. Vinegar eels, microworms, black worms, tubifex, and white worms are just a few. Yet larger earthworms are not often cultured and fed, depriving our medium and larger fish of this excellent food.
I culture earthworms in a large sweater box (around 1 1/2 X 2 feet and 8 inches deep) in a dry area on the basement floor against an outside wall where the temperature is around 65 degrees or lower. They will do well at warmer temperatures where white worms may die. I use 1/2 worm bedding and 1/2 peat moss for the medium, about 1 1/2-2 inches deep. Keep it moist but not soggy. These worms don't get much larger than 2 ½”, which is a perfect size for medium and larger sized fish. I feed them 1-minute oatmeal by mixing it into the soil occasionally. The soil gradually gets more moist if you keep it covered (recommended) so I will at times add some peat moss or worm bedding to refresh it and some moisture to get it to the correct wetness. I like a tight fitting cover to prevent them from crawling out, especially at night, and to keep bugs out.
They are a great food that larger fish really enjoy. For medium sized fish, harvest them with tweezers, cut them up in pieces with scissors, rinse, and feed. This is a great live food that is often missed, and as long as moisture is maintained, can be neglected for long periods of time and still be revived.