How to Identify Types of Jellyfish Species in Florida

To help aid in the identification of jellyfish in Florida, below are several species of jellyfish that wash up along Florida’s east coast from the Atlantic Ocean.

Portuguese Man-of-War (Physalia physalis)

Powerful sting, potentially lethal from allergic reactions

Portuguese Man-of-War aren’t jellyfish but a colony of small organisms called Siphonophorae.

The Portuguese Man-of-War can be identified from other types of jellyfish in Florida by its translucent blue, pink, green or purple gas-filled air sac which helps the sea creature travel long distances across the ocean by acting as a wind-driven sail.

A violet-colored stinging tentacle cluster mass underneath the Portuguese Man-of-War’s air sac can have tentacles that extend up to fifteen feet long.

Box Jellyfish (Chiropsalmus quadrumanus)

Powerful sting, lethal in high doses or from allergic reactions

Florida Box Jellyfish

Although the Florida species of box jellyfish does not pack the extreme potency of the infamous Australian box jellyfish dubbed the sea wasp, the species that washes up on Florida’s beaches can still be life-threatening and has a painful sting.

The box jellyfish can be identified by its box-shaped bell. On each of its four corners, there are stout, hand-like structures where up to nine tentacles dangle.

What makes this jellyfish more dangerous to beachgoers than the Portuguese Man o’ War is its translucent color which makes it harder for swimmers to see the box jellyfish nearby.

Also, the box jellyfish’s clear bell could be mistaken for other, less-venomous jellyfish that commonly wash up along Florida’s beaches.

Mauve Stingers (Pelagia noctiluca)

Powerful sting, potentially lethal from allergic reactions

Mauve Stinger Jellyfish In Florida
In May 2011, thousands of Mauve Stinger jellyfish washed up along Cocoa Beach, Florida. Brevard Times / File

As the name implies, Mauve Stingers are purple-red in color with darker spots. They range in size from 2 to 5 inches in diameter.

Cannonball Jellyfish (Stomolophus meleagris)

Mild sting, potentially lethal from allergic reactions and heart conditions

Cannonball jellyfish (pictured in top-left) have a 7 to 10-inch dome-shaped bell that is light in color with darker pigmentation around its edges.

Their short and stocky tentacles are located mostly underneath the dome which helps prevent accidental contact with humans.

By-the-Wind Sailors (Velella velella)

Slight itchiness, potentially lethal from allergic reactions

By-the-Wind Sailors, also called sea rafts or Velella velella, are small, oval sea creatures with a transparent sail and blue bottom.

By-the-Wind Sailors aren’t jellyfish. Like Portuguese Man-o-War, Velella are siphonophores – a colony of separate specialized organisms that only appear to be one marine animal.

Velella feed on plankton. Their natural predators are Blue Sea Dragons.

Velella usually remain far out in the open sea and are not often seen on Florida’s beaches unless a persistent wind blows these natural tiny blue sailboats onto the beach.

Blue Buttons (Porpita porpita)

Slight itchiness, potentially lethal from allergic reactions

Blue Button Jelly Fish

Blue Buttons are small, circular sea creatures with ‘spokes’ extending outwardly.

Blue Buttons aren’t jellyfish. They are Chondrophores – a colony of hydrozoan polyps that only appear to be one marine animal.

Blue Buttons feed on crustacean larvae. Their natural predators are Blue Sea Dragons.

Comb Jellyfish (Ctenophores)

Slight to no itchiness, potentially lethal from allergic reactions

Comb Jellyfish In Florida

Comb jellyfish are oblong, translucent and range from 2 to 5 inches in length. They are called combs because of the distinctive ridges on top,

Although Combs have an appearance like jellyfish, they are not true jellyfish because they come from a completely different phylum called Ctenophora.

One aesthetic benefit of Comb Jellies to beachgoers is that they glow at night with bioluminescence.

Moon Jellyfish (Aurelia aurita)

Slight to no itchiness, potentially lethal from allergic reactions

Moon Jellyfish Florida

Moon jellyfish are circular, translucent and range from 10 to 16 inches in diameter.