Sea apple

Care at a glance

Overview

The sea apple is a colorful, peaceful filter feeder that perches in the flow with its tentacles spread. It is difficult and best left to experienced reef keepers.

Caring for the sea apple

Keep the sea apple in an established reef of at least 20 gal (75 L), with moderate to strong, steady flow. Give it plenty of live rock to perch on and open room to move until it finds a spot it likes. Screen every pump and overflow intake, since it will crawl into anything that pulls water. Being drawn in is usually fatal to it and dangerous to the rest of the tank.

Hold the water at 75 to 81°F (24 to 27°C) with a pH of 8.1 to 8.4. Drip acclimate it slowly and handle it as little as possible.

The sea apple is a filter feeder. Feed it daily with phytoplankton and other fine suspended foods, dosed upstream of it rather than squirted onto its tentacles. It depends on a mature tank with real plankton in the water column to round out what you feed.

It is rated reef safe with caution because of its toxin, not any coral-eating habit. Never keep it with butterflyfish, large angelfish or other fish that pick at inverts, since a nipped sea apple is a dying sea apple. Treat any sea apple in obvious distress as a tank emergency and pull it at once. If one does die, do a series of water changes and run fresh carbon immediately.

Good to know

Pseudocolochirus violaceus is a filter-feeding sea cucumber in the family Cucumariidae. It is instantly recognizable by its plump violet to blue body, studded with orange to red tube feet. A crown of ten branched, sticky tentacles catches food from the water column. Unlike deposit-feeding cucumbers that eat sand, it captures suspended plankton and organic particles. It wipes each tentacle across its mouth in turn to swallow whatever has stuck to it.

In the wild

Sea apples are found across the Indo-Pacific, including the Red Sea, Sri Lanka, Vietnam and northern Australia. They anchor to rock and rubble in current-swept areas, where they can extend their tentacles into passing water.

Common questions

Related species

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