How much do seahorses weigh?

Seahorses vary widely in size and weight with most falling between 3 and 25 grams. Several dozen species of seahorse populate nearly all of the world's oceans, and they range in size from under half an inch to over a foot long.

There is a great variety of seahorse species, and each species displays considerable variation within populations. This diversity makes it difficult to generalize about the physical characteristics of all seahorses. The situation is further complicated because seahorses have an exoskeleton that usually grows long fringes or tendrils that contribute to its camouflage but also add to each individual's weight.