Snake sea cucumber (Synapta maculata) care guide

Group
Other invertebrates
Other names
Medusa worm, Spotted worm sea cucumber, Snake cucumber
Family
Synaptidae
Origin
Tropical western Indo-Pacific; reefs, seagrass and soft bottoms to about 20 m
Water
saltwater
Maximum size
200 cm
Temperature
22–26°C
pH
8.1–8.4
Hardness
dKH 8–12, SG 1.023–1.025
Care level
expert
Temperament
peaceful
Reef safe
with_caution

Care

Synapta maculata is a very long, thin, worm-like sea cucumber: typical adults are about 2 m long and some exceed 3 m, making it probably the longest sea cucumber in the world, though far from the heaviest. It is usually yellowish-brown with broad lengthwise stripes and dark patches, and has fifteen feathery tentacles around the mouth. Its skin contains microscopic anchor-shaped plates that make it feel sticky and help it move. In the wild it lives on reefs and on sand and seagrass beds down to about 20 m, constantly dabbing its tentacles on the seabed and seagrass to collect food particles. When disturbed it pulls its tentacles in, and if attacked it sheds sections of its body rather than throwing out its guts as many sea cucumbers do. This animal is suitable only for very large, mature systems with a big, healthy sand bed and a lot of natural food, and for experienced keepers. Most die slowly of starvation in normal tanks. It is easily sucked into pumps and overflows, so all intakes must be guarded. Water figures are standard reef conditions (general guidance). Toxin warning: sea cucumbers can release toxins (holothurins and related saponins) when stressed, injured or dead. Synapta maculata contains such compounds and noxious cells in its skin. A cucumber chewed up by a pump can poison a whole tank, so act fast if one dies or is damaged: remove it, change water and run activated carbon. Copper-based medicines and some plant fertilisers are toxic to shrimp, snails and most invertebrates. Sources: Wikipedia (en.wikipedia.org/wiki/Synaptamaculata). Checked October 2026.

Diet

A surface deposit feeder: its sticky tentacles are pressed onto sand, rock and seagrass to pick up detritus, micro-organisms and fine organic matter, then wiped into the mouth. It needs a large area of mature, life-rich sand and rock; supplements such as fine sinking foods and phytoplankton help but rarely make up the shortfall.

Breeding

Our sources do not cover its reproduction. Sea cucumbers generally spawn into the water and are not bred in aquaria; this species also breaks into pieces when attacked, which is a defence rather than a breeding method.

Compatibility and tank mates

Harmless to corals and fish while healthy, but listed 'with caution' because of the toxin risk if it is damaged by pumps or harassed by fish. Avoid fish that pick at invertebrates (puffers, triggers, some angelfish).

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

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