It catches insects and even small fish and tadpoles. The fisher spider grows 0.4 to 0.7 inches long. It creates a snare to catch flying insects. Water mites range from 0.1 to 0.2 inches long. They eat small worms, insects, and crustaceans.
Some mites are parasites.
Some swim and some crawl but all must come up to breathe. There are a number of species of earthworms or Oligochaeta . Tubifex are an inch long, are red, and live in tubes in bottom mud. Chaetogasters eat small animals with their large mouths and grow to half an inch. Deros build tubes in debris, grow to about half an inch, and have bristles.