Gonionemus vertens

Gonionemus is a genus of small marine hydrozoans, belonging to the phylum Cnidaria. These jellyfish have a bell-shaped body, typically around 15 mm in diameter, with hollow tentacles armed with stinging cells called nematocysts. The life cycle begins as a planula larva, which develops into a small, non-swimming polyp. This polyp then buds off medusae, which are the jellyfish stage. The medusae reproduce sexually, releasing gametes into the water, and fertilized eggs develop into new planula larvae.1

The species Gonionemus vertens is known for its venomous sting. Stings can cause burning sensations, blistering, swelling, and general weakness, with symptoms lasting several days. In severe cases, breathing difficulties and liver malfunction can occur. These jellyfish are found in warmer regions of the Atlantic and Indo-Pacific oceans and can pose a danger to swimmers.1