Definition

1. Noun:
   • A minute freshwater crustacean with a rounded body enclosed in a transparent shell, moving jerkily like a flea using its hairy, branched antennae.
   • A minute, free-swimming freshwater copepod characterized by a large central eye, a pear-shaped body, and long antennae used for locomotion; ecologically significant as part of food chains and as an intermediate host for parasitic worms affecting humans.

Usage Examples

• Noun:
  • The pond sample was teeming with water fleas, visible under the microscope.
  • Scientists study water fleas to monitor freshwater ecosystem health.
  • The water flea serves as an intermediate host for the Guinea worm parasite.

Advanced Usage

• In scientific contexts: The term "water flea" is a common name for organisms in the orders Cladocera (like ) and Copepoda. They are model organisms in ecological and toxicological studies.
  • The population density of water fleas is a key bioindicator of water quality.

Variants and Related Words

• Daphnia (n): A common genus of water flea, often used in aquarium fish food and laboratory research.
• Cyclops (n): A genus of one-eyed copepods also referred to as water fleas.

Synonyms

• Cladoceran (for the crustacean type with a shell).
• Copepod (for the free-swimming type).

Notes on Meaning

• The term broadly applies to two different types of small, jumping aquatic organisms but does not refer to actual fleas (insects). The name derives from their flea-like, hopping swimming motion.

Noun

1. minute freshwater crustacean having a round body enclosed in a transparent shell; moves about like a flea by means of hairy branched antennae
2. minute free-swimming freshwater copepod having a large median eye and pear-shaped body and long antennae used in swimming; important in some food chains and as intermediate hosts of parasitic worms that affect man e.g. Guinea worms