Pseudocolochirus (Sea Apple) Breeding Guide

How the filter-feeding sea apple Pseudocolochirus reproduces by broadcast spawning, why it is not home-bred, and the serious holothurin toxin risk it poses to a tank.

Overview

The sea apple (genus Pseudocolochirus) is an Indo-Pacific filter-feeding sea cucumber that reaches about 20 cm in length. The Australian form has a primarily purple body with red feet and purple-and-white tentacles. It feeds primarily on plankton, which it filters from the water with its tentacles, alternately bringing each tentacle to its mouth to scrape off captured food.

Reproductive Mode

Like other holothurians, sea cucumbers most commonly reproduce by releasing sperm and ova into the ocean water as broadcast spawners, with separate sexes in most species. Species-specific spawning data for Pseudocolochirus is not documented in the consulted sources, so only the general holothurian pattern is stated here.

Sexual Reproduction

Sea cucumber development generally proceeds through planktonic larval stages: a ciliated auricularia, followed by a barrel-shaped doliolaria, and then a pentacularia in which the tentacles appear. This extended planktonic phase is the route to new juveniles in the wild.

Common Challenges

The sea apple is not bred in home aquaria; planktonic larval rearing is beyond display-tank conditions. More importantly, sea apples release the toxic saponin holothurin when stressed, and this toxin can poison other aquarium inhabitants, which makes the animal hazardous in a community system.