Spaghetti worm (Loimia medusa) care guide

Group
Other invertebrates
Other names
Medusa worm, Kauna'oa
Family
Terebellidae
Origin
Tropical seas including the Indo-Pacific, Hawaii and the western central Atlantic; rubble, sand, tide pools and bays
Water
saltwater
Maximum size
30 cm
Temperament
peaceful
Reef safe
yes

Care

The spaghetti worm is a harmless, helpful hitchhiker that often arrives in live rock or sand. You usually see only its long, thin, bluish-white tentacles, which look like strands of spaghetti spreading over the sand and rock from a hidden tube. The worm lives in a tube made of shell fragments and gravel lined with a tough membrane. The body can reach about 30 cm and the tentacles about twice that, though aquarium animals are usually much smaller. Role: it is a deposit feeder. The sticky tentacles crawl over the surface and collect detritus and fine organic matter, carrying it back to the mouth. This makes it a useful part of the natural clean-up crew in a sand bed, and its presence is a sign of a healthy, mature system. Care: it needs no special care. A mature sand bed and normal reef feeding will sustain it. It should not be confused with harmful worms; it does not sting, bite or attack corals. Caveats: large numbers mean there is plenty of detritus, which may point to overfeeding. Tentacles can occasionally drape over corals but do no harm. Copper: copper-based medicines and some plant fertilisers are toxic to shrimp, snails and most invertebrates. Never dose copper in a tank holding this animal, and check fertiliser and medicine labels before use. Sources: Wikipedia (en.wikipedia.org/wiki/Loimiamedusa). Checked October 2026.

Diet

Deposit feeder: detritus, fine organic particles and leftover food picked up from the sand and rock with its tentacles. It needs no feeding of its own.

Breeding

Sexes are separate and it spawns into the water, with planktonic larvae. Spaghetti worms can become established in mature tanks from hitchhikers but are not deliberately bred.

Compatibility and tank mates

Reef safe and harmless to fish, corals and invertebrates. Wrasses, some crabs, hermits and sand-sifting fish may eat its tentacles.

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

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