Panagrellus redivivus
（重定向自Microworm）
The free-living nematode Panagrellus redivivus (sour paste nematode) is known to many aquarium enthusiasts and fishkeepers as the microworm. It is a tiny roundworm used as the first food for minuscule newly hatched fish, such as the popular pet fish betta. The microworm is widely used in aquaculture as food for a variety of fish and crustacean species.