Catostylus perezi, commonly known as the banana jellyfish, is a jellyfish in the family Catostylidae.

Description Catostylus perezi has a smooth domed bell that is 147 mm in diameter and around eight sensory structures called rhopalia. The jellyfish also presents eight oral arms that can grow up to 85 mm long. When alive, the color of the jellyfish ranges from blue to transparent, but when preserved, it turns a creamy white color. This jellyfish is distinguished from other groups because it lacks appendages around its bell-shaped area. Catostylus perezi has been observed in the coastal waters of the Southern Arabian Peninsula and Persian Gulf region.

Behavior and ecology Catostylus perezi move by thrusting their bell, which creates propulsion to help them get through the water. Due to having no control over which direction they go, they are passive feeders, feeding primarily on zooplankton and fish larvae using their oral arms. Though the jellyfish's sting is not harmful to humans, it does have nematocysts used to help aid in capturing prey and defending itself from predators. This species has shown to be very hardy with studies showing them being able to adapt to different environment changes.