Freshwater shrimp (Gammarus amphipods) (Gammarus spp.) care guide

Group
Other invertebrates
Other names
Amphipods, Scuds, Freshwater shrimp, Gammarus pulex, Side-swimmers
Family
Gammaridae
Origin
Widespread across the Northern Hemisphere (Holarctic) and into tropical Southeast Asia; Gammarus pulex is common in Britain
Water
freshwater
Maximum size
2 cm
Temperature
4–20°C
pH
7–8.5
Hardness
8–20 dGH
Minimum tank
10 litres
Care level
beginner
Temperament
peaceful
Lifespan
about 1 years

Care

Gammarus is a large genus of amphipods, with more than 200 species, found across the Northern Hemisphere and into tropical Southeast Asia. They are the familiar 'freshwater shrimp' or scuds of streams, ponds and ditches: small, sideways-flattened crustaceans up to about 2 cm that swim on their sides. Salt tolerance varies by species: Gammarus pulex lives only in fresh water, while Gammarus locusta lives in estuaries and sea water. The small amphipods that appear in reef tanks are usually other marine genera, but they play the same role. UK native: Gammarus pulex and several other Gammarus species are native to Britain. They need a coldwater (unheated) tank or pond, and should not be collected from the wild where that is not allowed. Wild-collected amphipods can carry parasites and diseases, so culture them rather than taking them from the wild. Helpful hitchhiker: amphipods often arrive with plants or pond water and are harmless and useful. They shred dead leaves and eat detritus and algae, and they are excellent live food for fish. In a tank with fish, numbers stay low. In a fishless coldwater tank or pond they can be cultured easily on leaf litter. Biosecurity: some non-native amphipods, such as the killer shrimp Dikerogammarus villosus, are invasive in Britain. Never release aquarium amphipods, and follow 'check, clean, dry' when moving nets or plants between waters. Copper: copper-based medicines and some plant fertilisers are toxic to shrimp, snails and most other invertebrates. Never treat a tank holding them with copper, check the label of any fertiliser or medicine, and keep nets and buckets used for copper-treated tanks separate. Sources: Wikipedia (en.wikipedia.org/wiki/Gammarus). Checked October 2026.

Diet

Detritus feeders and shredders. They eat dead and decaying leaves, algae, biofilm and leftover food, and will scavenge dead animals. In cultures, feed oak, beech or alder leaves, a little fish flake and blanched vegetables.

Breeding

Breeding is easy. The male carries the female clasped beneath him (amplexus) until she moults and they mate. She carries the eggs in a brood pouch under her body and the young hatch as tiny amphipods, with no larval stage. In a culture they breed all year in mild conditions.

Compatibility and tank mates

Harmless to fish and plants, though large numbers may nibble soft plants. Almost every fish eats them, so they are best kept with fish as food or in a separate culture. Avoid adding wild-caught amphipods to tropical tanks; most native species need cool water.

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

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