The red sea squirt lives solitarily and measures around 4 inches in length but can reach a maximum size of 8 inches.

The sea squirt’s body, swollen like a bladder, earns it the nickname « sea bladder » in french. It stands upright in its bright red to orange-red tunic, with a lighter hue on the less exposed side.

The red sea squirt’s covering, called the tunic, is granular and features two cylindrical tubes known as « siphons »: one vertical, standing upright like a chimney at the top, and the other horizontal near the upper third.

Sea water enters through the upper siphon, called the oral siphon, where it is drawn in and then expelled through the lateral siphon, called the cloacal siphon, after passing through a filtration system designed to capture microorganisms, both plant and animal, as well as the oxygen needed for respiration.

Each siphon is equipped with fine, silky cilia at its opening to detect and prevent the intrusion of particles that are too large.

The red sea squirt can be found from the surface down to depths of 328 feet.

It is found in the Mediterranean sea, where it is very common and also in the part of the Atlantic ocean close to the Mediterranean extending up to Portugal.

The red sea squirt lives on rocky substrates or in seagrass beds, particularly around the rhizomes, but always in sheltered, low-light conditions.

It is commonly seen on the walls of dimly lit drop-offs, at the entrance or on overhangs of rocky crevices.

The red sea squirt feeds on microorganisms it traps through active filtration of seawater.

It reproduces sexually. Eggs are fertilized by sperm to produce larvae, which then settle on a substrate and develop into new sea squirts.

The opening of the upper siphon can appear as a cross when it is closed.

The red sea squirt can retract its body by expelling all the water it contains.

It is one of the most widespread sea squirt species in the Mediterranean.

Observe the siphons, which are very clearly visible. They react to even slight changes in the surrounding water pressure.

Examine the tips of the siphons to determine whether they are open or closed.