The weight of a jellyfish can vary significantly depending on the species. Generally, jellyfish are not very heavy because their bodies are composed mostly of water—around 95% of their total mass. For example, a common moon jellyfish (Aurelia aurita) can weigh between 0.1 to 0.2 kilograms (about 0.2 to 0.4 pounds).
On the other hand, larger species, like the lion’s mane jellyfish (Cyanea capillata), can reach weights of up to 200 kilograms (about 440 pounds) or more when fully expanded. However, these weights can fluctuate due to environmental factors and the jellyfish’s water content.
In summary, while small jellyfish might weigh just a few grams, the larger species can weigh much more, making it essential to consider the specific type of jellyfish when discussing their weights.