Hydractinia aggregata- Hydractinia altispina
- Hydractinia angusta
- Hydractinia apicata
- Hydractinia arborescens
- Hydractinia arctica
- Hydractinia arge
- Hydractinia bayeri
- Hydractinia carica
- Hydractinia cytaeiformis
- Hydractinia denhami
- Hydractinia diogenes
- Hydractinia echinata
- Hydractinia gorgonoides
- Hydractinia hebetispina
- Hydractinia kaffaria
- Hydractinia kaffraria
- Hydractinia marsupialia
- Hydractinia minoi
- Hydractinia monocarpa
- Hydractinia multispina
- Hydractinia ocellata
- Hydractinia parvispina
- Hydractinia polyclina
- Hydractinia proboscidea
- Hydractinia sandrae
- Hydractinia sarsii
- Hydractinia symbiolongicarpus
- Hydractinia symbiopollicaris
- Hydractinia vallini
- Hydractinia verde