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Translucent blue box jelly with long trailing tentacles drifting against a black background

Mangrove box jelly

Tripedalia cystophora

Not on exhibit
Animal type
Invertebrates
Ecosystem
Coastal waters
Relatives
Sea wasp; Family: Tripedaliidae
Diet
Crustaceans, copepods
Range
Gulf of Mexico, Caribbean and Atlantic Ocean from Florida to Puerto Rico
Size
Up to 0.5 inches (1.3 cm) diameter

Meet the mangrove box jelly

That square-shaped bell gives the box jelly its name. It’s one of the smallest jellies in the world—an adult grows to about the size of a grape.

Natural history

While other box jellies can have lethal stings, the mangrove box jelly is harmless to humans. This jelly faces its greatest danger from humans, due to habitat destruction.

Conservation

The mangrove box jelly lives in tropical mangrove forests in Central America. The larvae settle on mangrove roots and form polyps. Adult jellies live in between the roots of the trees, searching for copepods to eat.

Mangrove forests are among the most threatened ecosystems on our planet. They’re cleared for development, agriculture, and fish and shrimp farms. Pollution and sediment flow from land into these shallow coastal habitats, threatening the diverse marine life that lives there. Without this nurturing habitat, it's unlikely this tiny jelly would survive.

Cool facts

  • Unlike most jellies, which can merely sense light or dark, the mangrove box jelly has multiple sets of eyes that it uses to help it navigate toward groups of copepods. Each set of eyes is called a rhopalium. There are two complex eyes—each with a lens, cornea and retina—and one or more simple eyes in each rhopalium.

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