JELLYFISH - SCYPHOZOANS There are many types of jellyfish; the smallest are only one centimeter wide and the largest jellyfish’s bell (cyanea capillata) can grow up to one meter wide. Jellyfish exists for 98% out of water. They swim or float in all our oceans and some even live in sweet water. Jellyfish have a soft body and tentacles which they use to catch prey. Some of these tentacles posses a venom which is excreted through stinging cells called nematocysts. The nematocysts act as small harpoons that fire into prey and inject them with paralyzing toxins. Jellyfish posses an elementary nervous system rather than a brain which consists of receptors capable of detecting light, odor and other stimuli. They have an opening located at the bottom-center which is both used as mouth and anus. Four to eight oral arms are used to transport food towards the mouth. They are carnivorous, feeding on a variety of zooplankton, comb jellies and occasionally other jellyfish. Some of the larger species are capable of capturing large crustaceans and other marine organisms. Jellyfish do have predators like batfish, sunfish and turtles. In some parts of Asia, some jellyfish are even considered a delicacy by humans. If stung by a jellyfish, the victim should carefully remove the tentacles. This is best done in the water the animals live in. As long the tentacles remain on the skin they will continue to discharge venom. Don't use other substances which are not known by the animal as it will keep on protecting itself by ejecting venom. Recovery periods can vary from several minutes to several weeks. Specimen like the box jellyfish (genus carybdea) and carukia barnesi are able to kill humans.