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Jellyfish: Not Fish At All! Unpacking the Biological Differences
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News18•21-09-2026, 18:15
Jellyfish: Not Fish At All! Unpacking the Biological Differences
- •Jellyfish are invertebrates, lacking backbones, hearts, brains, and blood, unlike true fish which possess complex organ systems.
- •They breathe by absorbing dissolved oxygen directly through their skin via diffusion, without gills or a respiratory system.
- •Taxonomically, jellyfish belong to the phylum Cnidaria (like sea anemones and corals), while fish are in the phylum Chordata.
- •Jellyfish move using primitive jet propulsion and rely on ocean currents, contrasting with fish's dynamic fin and tail movements.
- •They capture prey with specialized stinging cells called cnidocytes, injecting venom, unlike fish that use jaws and teeth.
Key Questions Answered
True fish belong to the phylum Chordata with a backbone and skeletal structure, while jellyfish belong to the phylum Cnidaria as soft-bodied invertebrates sharing a biological family with corals and sea anemones.
Jellyfish completely lack gills, lungs, or a respiratory system, opting instead to absorb dissolved oxygen directly through their thin epidermal membranes via simple diffusion.
Jellyfish use specialized stinging cells called cnidocytes located on their tentacles that act like tiny harpoons to inject paralyzing venom into prey on contact.
