Introduced coelenterates-hydrozoans:
| Coelenterates-Hydrozoans | Antennella secundaria | a thecate hydroid |
| Coelenterates-Hydrozoans | Anthohebella parasitica | |
| Coelenterates-Hydrozoans | Blackfordia virginica | Black Sea jellyfish |
| Coelenterates-Hydrozoans | Cladonema radiatum | |
| Coelenterates-Hydrozoans | Cladonema uchidae | a hydrozoan |
| Coelenterates-Hydrozoans | Clava multicornis | club hydroid |
| Coelenterates-Hydrozoans | Clytia hemisphaerica | hydroid |
| Coelenterates-Hydrozoans | Clytia latitheca | |
| Coelenterates-Hydrozoans | Cordylophora caspia | freshwater hydroid |
| Coelenterates-Hydrozoans | Corymorpha sp. | hydroid |
| Coelenterates-Hydrozoans | Craspedacusta sowerbyi | freshwater jellyfish |
| Coelenterates-Hydrozoans | Dynamena crisiodes | a hydroid |
| Coelenterates-Hydrozoans | Eudendrium sp. | |
| Coelenterates-Hydrozoans | Garveia franciscana | hydroid |
| Coelenterates-Hydrozoans | Garveia humilis | hydroid |
| Coelenterates-Hydrozoans | Gonionemus vertens | clinging jellyfish |
| Coelenterates-Hydrozoans | Gonothyraea clarki | hydroid |
| Coelenterates-Hydrozoans | Halecium beanii | a hydroid |
| Coelenterates-Hydrozoans | Halopteris polymorpha | |
| Coelenterates-Hydrozoans | Maeotias marginata | Black Sea jellyfish |
| Coelenterates-Hydrozoans | Moerisia lyonsi | |
| Coelenterates-Hydrozoans | Moerisia sp. | |
| Coelenterates-Hydrozoans | Obelia bidentata | doubletoothed hydroid |
| Coelenterates-Hydrozoans | Obelia dichotoma | hydroid |
| Coelenterates-Hydrozoans | Obelia spp. | a hydrozoan |
| Coelenterates-Hydrozoans | Pennaria (Halocordyle) disticha | Christmas tree hydroid |
| Coelenterates-Hydrozoans | Plumularia floridana | |
| Coelenterates-Hydrozoans | Plumularia strictocarpa | |
| Coelenterates-Hydrozoans | Sarsia tubulosa | clapper hydromedusa |
| Coelenterates-Hydrozoans | Sertularella areyi | |
| Coelenterates-Hydrozoans | Sertularella tongensis | |
| Coelenterates-Hydrozoans | Sertularia ligulata | |
| Coelenterates-Hydrozoans | Synthecium megathecum | |
| Coelenterates-Hydrozoans | Thyroscyphus fruticosus | a hydroid |
| Coelenterates-Hydrozoans | Tridentata humferi | |
| Coelenterates-Hydrozoans | Tridentata ligulata | |
| Coelenterates-Hydrozoans | Tridentata turbinata | |
| Coelenterates-Hydrozoans | Tubularia crocea | a hydroid |
| Coelenterates-Hydrozoans | Turritopsis nutricula | hydroid |
| Coelenterates-Hydrozoans | Ventromma halecioides |