Atlantic ditch shrimp (Palaemon varians) care guide

Group

Shrimp

Other names

Palaemonetes varians, Palaemon variabilis, Variable shrimp, Grass shrimp (trade name), Ditch shrimp

Family

Palaemonidae

Origin

Native to Britain; brackish coastal waters from the Baltic Sea and British Isles to the western Mediterranean

Water

brackish

Maximum size

5 cm

Temperature

5–22°C

Minimum tank

40 litres

Care level

beginner

Temperament

peaceful

Care

The Atlantic ditch shrimp, or variable shrimp, is a small, see-through prawn of brackish ditches, saltmarsh pools and lagoons. It is native to Britain and ranges from the Baltic Sea to the western Mediterranean. It grows to about 5 cm and is mostly clear with faint markings, which change with background and diet. It was long known as Palaemonetes varians; that genus has been merged into Palaemon, so the current name is Palaemon varians. Some UK shops sell it simply as grass shrimp. Native species: because it is a British native, it needs a coldwater (unheated) tank and does not want tropical temperatures. Do not collect it from the wild where that is not allowed, for example in nature reserves or protected sites, and never release aquarium shrimp back into the wild. Tank set-up: an unheated tank of 40 litres or more, kept in a cool room, with sand or fine gravel, stones and hardy plants or macroalgae. Keep a small group. It is often used as live food or as a scavenger in temperate marine and brackish tanks. Water: it is never found in fully marine conditions, but it tolerates a wide range of salinity, from almost fresh to brackish, and survives long periods between 1 °C and 30 °C. Brackish water (a specific gravity of roughly 1.005–1.015) and room temperature or cooler suit it best; very warm water shortens its life. Behaviour and role: generally peaceful with similar-sized animals and an active scavenger that eats leftover food, algae and plant matter, which makes it useful for tidying brackish tanks. Like all shrimp it spends much of the day picking biofilm off surfaces. Copper: copper-based medicines and some plant fertilisers are toxic to shrimp, snails and most invertebrates. Never dose them in a tank holding this animal, check the label of any treatment or fertiliser, and use a separate hospital tank for fish. Sources: Wikipedia (en.wikipedia.org/wiki/Palaemonvarians). Checked October 2026.

Diet

Omnivorous scavenger. It eats leftover fish food, algae, plant matter and biofilm, and will take small live and frozen foods such as brine shrimp and mysis. Feed small amounts of sinking pellets, flake and frozen food.

Breeding

Females carry eggs under the abdomen and the young hatch as larvae, which develop in brackish water and need very fine live food such as rotifers and newly hatched brine shrimp. Raising the larvae is possible in a separate brackish rearing tank but takes some effort. Females are usually larger and fuller-bodied than males.

Compatibility and tank mates

Peaceful with similar-sized fish and invertebrates, but larger fish, crabs and gobies will eat it; it is often kept as natural live food for coldwater marine fish. It may pick at very small or weak animals. Not suited to tropical tanks because it needs cool water.

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