Common name: Incandescent Sea Squirt

General information

The Incandescent Sea Squirt, Phallusia julinea, is a solitary ascidian found in tropical marine waters. It is known for its translucent body and the ability to emit a soft, glowing light, which is not commonly observed in other tunicates. This bioluminescence is thought to be a form of defense against predators.

Care

Phallusia julinea requires a well-established aquarium with stable water conditions and low to moderate water flow. They are filter feeders, so water quality is paramount. They feed on phytoplankton and suspended organic particles, and hobbyists should ensure a continuous supply of food with the help of a plankton reactor or dosing liquid phytoplankton.

Reproduction

Sea squirts are hermaphrodites, possessing both male and female reproductive organs. They can reproduce both sexually, by releasing sperm and eggs into the water column where fertilization occurs, and asexually through budding. In the aquarium, sexual reproduction is less common, but budding can occasionally be observed.

Habitat

Phallusia julinea is typically found in shallow waters attached to hard substrates such as rocks or coral rubble. They are often seen in areas with good water circulation, which is essential for their filter-feeding lifestyle. Their natural range includes the Indo-Pacific region, from the Red Sea to the Western Pacific.