Siphonostomatoida is an order of copepods, containing around 75% of all the copepods that parasitise fishes.

[1] Their success has been linked to their possession of siphon-like mandibles and of a "frontal filament" to aid attachment to their hosts.

[2] Most are marine, but a few live in fresh water.

[3] There are 40 recognised families:[4]

This copepod-related article is a stub.