Panagrellus redivivus


The free-living nematode Panagrellus redivivus, is known to many aquarium enthusiasts and fish keepers as the micro-worm. It is a tiny roundworm used as the first food for larger kinds of newly-hatched fish, such as larval common carp. The microworm is widely used in aquaculture as food for a variety of fish and crustacean species.
One of thirteen currently recognized species of Panagrellus, P. redivivus is about 50 μm in diameter and just over 1 mm in length, barely visible to the naked eye. Subsisting on yeast, it is easily cultured at home on a substrate of flour paste or porridge inoculated with dry yeast. Females reach maturity in about three days and deliver live young rather than eggs, as most nematodes produce.
The microworm has been used in genetic analysis studies, but not nearly as universally as its relative, Caenorhabditis elegans.
In Vietnamese cuisine, cơm mẻ is an ingredient appears in many dishes such as buffalo meat and fish soup thanks to its sourness. Cơm mẻ is the cooked rice being lactic fermented by yeast and maintained with the existence of P. redivivus.