Cnidaria is a phylum (not a family) that includes jellyfish and hydras. They are defined by their soft, radially symmetrical bodies, a single-opening digestive cavity and specialized stinging cells used for defense and hunting.
Until the spring 2025 season, these were never important, but as a phylum crossed the 10% RRA at Kaikoura.
Image from www.mesa.edu.au/cnidaria/ The Tunicates or sea squirts are marine invertebrate filter feeders, and a sub-phylum within the Chordata Phylum. Two genera (Salpa and Ihlea) are both salps that are free-floating and belong to the family of Salpidae and look a lot like jellyfish but are not related to Cnidaria.
source iNaturalist