Guardian Nature School Team Contact Blog Project Noah Facebook Project Noah Twitter

A worldwide community photographing and learning about wildlife

Join Project Noah!
nature school apple icon

Project Noah Nature School visit nature school

Stinging Hydroid

Aglaophenia cupressina


Hydroids are a life stage for most animals of the class Hydrozoa, small predators related to jellyfish. Some hydroids such as the freshwater Hydra are solitary, with the polyp attached directly to the substrate. When these produce buds, they become detached and grow on as new individuals. The majority of hydroids are colonial. The original polyp is anchored to a solid substrate and forms a bud which remains attached to its parent. This in turn buds and in this way a stem is formed. The arrangement of polyps and the branching of the stem is characteristic of the species. Some species have the polyps budding directly off the stolon which roots the colony. The polyps are connected by epidermis which surrounds a gastrovascular cavity. The epidermis secretes a chitinous skeleton which supports the stem and in some hydroids, the skeleton extends into a cup shape surrounding the polyp. Most of the polyps are gastrozooids or feeding polyps but some are specialised reproductive structures known as gonozooids. In some species, further specialised zooids are formed


This particular Hydroid stings, hence its name. It is not particularly poisonous/dangerous but its sting results in an itchy rash that can irritate for up to a week or more!

Species ID Suggestions

Sign in to suggest organism ID

No Comments

Spotted by

Batangas, Philippines

Spotted on Apr 13, 2014
Submitted on Apr 19, 2014

Related Spottings

Hydrozoan Blue Button White Stinger Blue Button

Nearby Spottings

Nemo - False Clownfish Octopus Fingerprint Shrimp Occelated Blue-ringed Octopus/Mototi Octopus


Noah Guardians
Noah Sponsors
join Project Noah Team

Join the Project Noah Team