Mysid shrimp (Mysidopsis bahia) care guide

Group
Shrimp
Other names
Americamysis bahia, Opossum shrimp, Mysis shrimp
Family
Mysidae
Origin
US Atlantic coast from Rhode Island to Florida and the Gulf of Mexico, in estuaries and seagrass
Water
saltwater
Maximum size
1 cm
Care level
intermediate
Temperament
peaceful
Reef safe
yes

Care

Mysidopsis bahia is now correctly called Americamysis bahia; the older name is still widely used in the literature and the trade. It is a tiny mysid, or opossum shrimp, reaching only about 1 cm (females are the larger), transparent with a yellowish, brownish or blackish tinge. It is not a true shrimp but belongs to its own order, Mysida. It is an estuarine animal from the US east coast and Gulf of Mexico, living just above sandy or muddy bottoms in shallow water, often in seagrass, and rising to the surface at night to feed. It tolerates a very wide range of salinity (from almost fresh to strongly salty water, most often around normal sea water), which makes it easy to culture. It is widely bred for laboratory toxicity testing because it is sensitive to pollutants, small and fast-breeding. In the hobby it is kept mainly as a live food culture for seahorses, pipefish, dragonets and other fussy feeders, and as a natural food population in refugiums and reef tanks. A culture tank needs gentle aeration, no strong pumps or filters that suck up the mysids, a little shelter such as macroalgae, and regular light feeding. Our sources give no temperature range; normal room-to-tropical marine temperatures are general guidance. Fish in a display will quickly eat them, so keep the breeding stock separate. Copper-based medicines and some plant fertilisers are toxic to shrimp, snails and most invertebrates. Sources: Wikipedia (en.wikipedia.org/wiki/Americamysisbahia). Checked October 2026.

Diet

An omnivore. Its wild diet has not been studied directly, but a close relative eats plant debris, copepods and diatoms. Cultures are usually fed newly hatched brine shrimp (Artemia) nauplii, which are the standard laboratory food, along with phytoplankton or fine powdered foods. Do not overfeed, as fouled water crashes cultures.

Breeding

Breeds fast and easily, which is why it is a laboratory standard. Females mature at about 12–20 days old, depending on food and temperature. Eggs are fertilised and develop inside a brood pouch under the female's thorax (hence 'opossum shrimp'), and after 4–6 days she releases 5–7 fully formed young. These swim in open water for about a day and then settle near the bottom. Each female can produce several broods over a few months. Separate or shelter the young, as adults may eat them when food is short.

Compatibility and tank mates

Harmless to everything and reef safe. Almost any fish will eat it, which is the point of keeping it as live food. In a refugium with no fish it can form a self-sustaining population that sends a trickle of live food to the display.

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

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