Solvin Zankl / Hydroids (Bougainvillia britannica) North Sea, Germany

Jan Hamrsky / Brown hydra (Hydra oligactis) polyps attached to the stone, Europe, September, controlled conditions

Jan Hamrsky / Brown hydra (Hydra oligactis) digesting the prey enclosed within the body cavity, Europe, September, controlled conditions

Jan Hamrsky / Brown hydra (Hydra oligactis) with two buds on the body wall, extending its tentacles, Europe, September, controlled conditions

Alex Mustard / Scalyhead sculpin (Artedius harringtoni) resting among Bushy pink-mouth hydroids (Ectopleura crocea), Browning Pass, Vancouver Island, British Columbia, Canada, Queen Charlotte Strait, Pacific Ocean.