Gold-mouth sea squirt (Polycarpa aurata) care guide

Group
Other invertebrates
Other names
Ox heart ascidian, Ink-spot sea squirt, Gold-mouth tunicate, Golden sea squirt
Family
Styelidae
Origin
Tropical eastern Indian Ocean and western Pacific: the Philippines, Indonesia, Timor-Leste and northern Australia; 5–50 m
Water
saltwater
Maximum size
15 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
yes
Flow
Moderate to strong

Care

The gold-mouth sea squirt is a solitary tunicate shaped like a hollow urn, 5–15 cm tall, with two openings (siphons): one on top and one on the side. The outside is white with purple and orange patches and purple lines, and the inside is yellow to orange, showing around the rim of the siphons. Tunicates are not corals or sponges; they are in fact distant relatives of vertebrates. Our sources have little on this species; the figures are general guidance, not from a source. Tank set-up: a large, mature reef tank with moderate to strong flow and plenty of fine suspended food. Attach it to rock where currents reach both siphons. Hydroids and algae may grow on its outside. Water: about 22–26 °C, pH 8.1–8.4, dKH 8–12 and specific gravity 1.023–1.025. Feeding: it pumps water in through the top siphon, filters out phytoplankton, bacteria and other fine particles, and pumps water out of the side siphon. Feeding warning: filter feeders like this are hard to keep fed in home aquariums and many slowly starve over weeks or months, even in good reef tanks. Only buy one if you can feed it suitable fine foods every day, and check it is eating before you buy. Copper: copper-based medicines are toxic to shrimp, snails and most invertebrates, and some plant fertilisers carry copper too. Never treat a display tank holding this animal with copper; treat fish in a separate hospital tank, and drip-acclimatise new arrivals slowly. Sources: Wikipedia (en.wikipedia.org/wiki/Polycarpaaurata). Checked October 2026.

Diet

Filter feeder: phytoplankton, bacteria and very fine organic particles. Feed live or bottled phytoplankton and fine liquid foods daily. A tank with a refugium and high plankton production helps.

Breeding

Sea squirts like this are hermaphrodites that release eggs and sperm into the water; the larvae look like tiny tadpoles and swim for a short time before settling. Not bred in aquariums.

Compatibility and tank mates

Reef safe and peaceful. Angelfish, butterflyfish, puffers and some nudibranchs may nip it. Keep it out of reach of stinging corals.

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

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