Seed shrimp (ostracods) (Cypridopsis vidua) care guide

Group
Other invertebrates
Other names
Seed shrimp, Ostracod, Mussel shrimp, Cypridopsis ostracod
Family
Cyprididae
Origin
Freshwater ponds, lakes and ditches; the genus is found worldwide
Water
freshwater
Care level
beginner

Care

Seed shrimp, or ostracods, are tiny crustaceans enclosed in a two-part shell like a seed or a minute clam, with legs poking out between the halves. Cypridopsis vidua is a common freshwater ostracod, well under a millimetre long, often with darker markings on a pale greenish shell. It scurries over glass, plants and substrate. Our sources have little on this species; the figures are general guidance, not from a source. How it arrives: in water, plants, moss and decorations from other tanks, ponds and nurseries. Numbers boom in tanks with plenty of food and few fish. Harmless hitchhiker: seed shrimp are harmless to fish, shrimp, snails and plants, and eat biofilm, algae and leftover food. They are eaten by most small fish, which keeps numbers down. A big population is a sign of overfeeding or excess organic matter, not a danger in itself. To reduce them, feed less, siphon the substrate and add small fish that hunt them, or simply leave them as part of the clean-up crew. Copper: copper-based medicines and some plant fertilisers are toxic to shrimp, snails and most other invertebrates. Never dose them in a tank holding this animal, and read the label of any treatment, fertiliser or algae remover before use. Sources: Wikipedia (en.wikipedia.org/wiki/Cypridopsis). Checked October 2026.

Diet

Grazes biofilm, algae, bacteria and detritus, and eats leftover fish and shrimp food.

Breeding

Reproduces quickly; in Cypridopsis vidua most populations are made up of females that reproduce without males. Eggs are laid on surfaces and hatch into tiny larvae that moult several times before reaching adult size.

Compatibility and tank mates

Harmless to all aquarium animals and plants. Eaten by small fish such as tetras, rasboras, killifish and gouramis.

Last updated 8 October 2026. Community-edited care guide on Aquatic-Auctions.

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