Jellyfish have no brain, heart, bones or eyes. They have a smooth, bag-like body and tentacles stinging cells. They use their stinging tentacles to stun or paralyze prey before eating and quickly digesting their food. The jellyfish’s mouth is found in the center of its body. They can be bio-luminescent, and not all species sting (Thank god for that, I held one). They survive on fish, shrimp, crabs, tiny plants and even other species of jellyfish. They make excellent food for turtles, which explains their abundances near turtle hatcheries, like this one here in Sri Lanka.