C haetognaths are in a separate Phylum by themselves. Characterized by a slender, transparent body, relatively large caudal fin, and anterior spines on either side of the mouth, these voracious meat-eaters catch large numbers of copepods, swallowing them whole. They are also reported to prey on early larval stages of fish, often attacking and consuming prey larger then themselves.
Chaetognaths alternate between swimming and floating.
The fins along their body are not used to swim, but rather to help them float. They use the muscles that run the length of their body to dart forward. Only two species are common in B.C. waters, but some deep-water species may be collected in surface tows on occasion.