The jellyfish is a carnivore and traps its prey with its tentacles. The tentacles have thousands of nematocysts, which are stinging cells. These cells inject a venom which will either paralyse or kill the prey. The potency of the venom is different in the various types of jellyfish. Certain types of jellyfish like the box jellyfish, has a venom that can kill an adult human being within minutes.
Most jellyfish just drift in the waters, with their jellyfish tentacles spread out. When it encounters a prey the tentacles release the venom, and the jellyfish ingests it into its mouth with the help of its oral arms. Some jellyfish who have the ability to swim well, will actively chase their prey.
All the types of jellyfish eat plankton, which are microscopic plants and animals drifting in the water. The jellyfish will also eat fish eggs and larvae of other marine animals. It will also feed on mollusks and crustaceans which are marine animals with a hard shell, having jointed legs and no backbone. Certain species of jellyfish will feed on other jellyfish as well.
The Lion's mane jellyfish can grow to a size of more than two meters in diameter. They have a powerful sting and will reel in their prey with their sticky tentacles. Research has shown that the Lion's mane will not grow properly unless its diet, consists of creatures with a gelatinous body. So this jellyfish is known to eat other smaller jellyfish and also jellyfish babies. The main jellyfish that the Lion's mane feed on, is the moon jellyfish. The Lion's mane is known to devour and digest, moon jellies as big as themselves. This jellyfish is known also to eat other fishes, crstaceans and a wide range of planktonic animals.
The moon jellyfish is a creature that is commonly found almost everywhere, as it is able to live in varied temperatures and waters with different salinity levels. This jellyfish has a bowl-shaped body, with small tentacles trailing along its circumference. Its diet mainly consists of small crustaceans and other small marine life forms. It also feeds on the zooplankton and mollusks. This jellyfish is also the one which is commonly found in aquariums and people keep them as pets as well. While in captivity their diet consists of baby brine shrimp, which is two days old and black worms. It can eat a lot of brine shrimp, and so you might need another tank to hatch and raise enough of brine shrimp to satisfy this jellyfish.
Written by Nathan Dickerson and Sudarsana Sinha.