Whether jellyfish are poisonous or not. According to relevant data, jellyfish have tentacles, which have a special structure and can release venom. Generally, if you are stung by a jellyfish, you will only feel burning pain and redness. All jellyfish are carnivores. They feed on fish and plankton. But when hunting, jellyfish are very passive and only prey on animals that swim towards them. They use stinging cells on their antennae to sting or kill their prey, and then send food to their mouths and digestive cavities. Most jellyfish are almost transparent, and it is difficult for enemies to find them. Some jellyfish glow and attract prey through the faint light from their bodies.