''Halocynthia aurantium'', commonly known as the sea peach, is a species of

tunicate A tunicate is a marine invertebrate animal, a member of the subphylum Tunicata (). It is part of the Chordata, a phylum which includes all animals with dorsal nerve cords and notochords (including vertebrates). The subphylum was at one time ca ...

in the order

Stolidobranchia Stolidobranchia is an order of tunicates in the class Ascidiacea.Lambert, G.; Gittenberger, A.; Sanamyan, K. (2015)Stolidobranchia.In: Shenkar, N.; Gittenberger, A.; Lambert, G.; Rius, M.; Moreira Da Rocha, R.; Swalla, B.J.; Turon, X. (2015) Asci ...

. Sea peaches are commonly found in the northern

Pacific ocean The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...

, ranging from the

Arctic Sea The Arctic Ocean is the smallest and shallowest of the world's five major oceans. It spans an area of approximately and is known as the coldest of all the oceans. The International Hydrographic Organization (IHO) recognizes it as an ocean, a ...

south to

Puget Sound Puget Sound ( ) is a sound of the Pacific Northwest, an inlet of the Pacific Ocean, and part of the Salish Sea. It is located along the northwestern coast of the U.S. state of Washington. It is a complex estuarine system of interconnected ma ...

, and most common in the

Bering Sea The Bering Sea (, ; rus, Бе́рингово мо́ре, r=Béringovo móre) is a marginal sea of the Northern Pacific Ocean. It forms, along with the Bering Strait, the divide between the two largest landmasses on Earth: Eurasia and The Ameri ...

at a depth of 40 to 100 metres. The sea peach is typically barrel shaped, growing to a height of 18 centimetres, and its body is attached directly to the substrate. It is usually red or orange with a smooth or wrinkled tunic. There are two siphons at the top. The sea peach is preyed upon by crabs and sea stars.

References

Stolidobranchia Animals described in 1787 {{tunicata-stub This sea peach is in the same family as a sea onion, Boltenia Ovifera Sea Peach Synopsis, https://www.afsc.noaa.gov/groundfish/HAPC/SeaPeach_synopsis.htm.