Cnidarians Known as Hydroids: Animals Looking Like Plants

Once again we dive into Cnidaria, a large phylum that contains approximately 10,000 species. Phylum members include many animals that attract attention because of their bright colors: sea anemones, corals, sea pens, gorgonians and jellyfish. These creatures can afford to flaunt their beauty because most of them have defensive polyps loaded with nematocysts (also called cnidocytes) that can fire venomous miniature harpoons. Lucky for us, most of these weapons are too tiny to penetrate our skin.