What kind of invertebrate is a jellyfish?

A jellyfish is a cnidarian.

Cnidarians are a group of aquatic invertebrates that include jellyfish, corals, sea anemones, and hydroids. They are characterized by:

* Radial symmetry: Their bodies are arranged around a central axis.

* Tentacles: They have tentacles that are armed with stinging cells called nematocysts.

* Two distinct body forms: Most cnidarians have two distinct body forms: a polyp (sessile) and a medusa (free-swimming). Jellyfish are in the medusa form.