Yellow sea cucumber (Colochirus robustus) care guide

Group
Other invertebrates
Other names
Robust sea cucumber, Yellow sea apple (misapplied), Yellow cucumber
Family
Cucumariidae
Origin
Central Indo-Pacific, including the Philippines and Indonesia, on rocks and reefs in moving water to about 25 m
Water
saltwater
Maximum size
7 cm
Temperature
22–26°C
pH
8.1–8.4
Hardness
dKH 8–12, SG 1.023–1.025
Minimum tank
150 litres
Care level
expert
Temperament
peaceful
Reef safe
with_caution
Lifespan
1–5 years
Flow
Moderate to strong

Care

The yellow sea cucumber is a small, bright yellow cucumber up to about 7 cm, roughly cylindrical with five shallow ridges covered in finger-like bumps, sometimes grey between the ridges. It has about eight feathery feeding tentacles and three rows of tube feet underneath. It clings to rocks and reefs where water moves moderately to fast, in shallow tropical waters of the central Indo-Pacific. Set-up: a mature reef tank of 150 litres or more with live rock and moderate to strong flow. It usually settles in the current and spreads its tentacles to feed. LiveAquaria gives 22–26 °C, pH 8.1–8.4, dKH 8–12 and SG 1.023–1.025 and classes it as Expert Only. Drip acclimatise; it does not tolerate high nitrate. Feeding warning: filter feeders like this are hard to keep fed in aquariums and many slowly starve over weeks or months, even in good tanks. Signs it is going hungry are shrinking and losing feeding tentacles; feed more often and target the food. Toxins: sea cucumbers can release toxins (holothurin) when stressed, injured or dying, and in a closed tank this can kill fish and other animals. Cover pump intakes and overflows, keep activated carbon to hand, and remove a dying cucumber at once. LiveAquaria notes the risk is rare unless the cucumber gets sucked into an uncovered pump or overflow. 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: LiveAquaria (liveaquaria.com/products/sea-cucumber-yellow-expert-only); Wikipedia (en.wikipedia.org/wiki/Colochirusrobustus). Checked October 2026.

Diet

A suspension feeder. It catches plankton and organic particles on its feathery tentacles and wipes them into its mouth. Feed liquid or dried phytoplankton and zooplankton several times a week, directed into the current upstream of it. Stirring the sand now and then releases bacteria and detritus that it can catch.

Breeding

It can reproduce sexually, and LiveAquaria notes a small group may spawn in a home tank. It can also split in two, each half regrowing the missing parts, which has been seen in tanks; it may mean stress or good health. Larvae are not raised in home aquariums.

Compatibility and tank mates

Peaceful and harmless to corals and fish, but its toxins make it a risk in any tank. Avoid fish that pick at invertebrates, such as puffers, triggers, large angelfish and some butterflyfish, which stress it. Guard pump intakes.

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

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