I came across this Hydra in my pond water microorganism aquarium. Hydra is an invertabrate microanimal, so named because when cut into pieces each piece can regenerate into an entire Hydra. They are carnivores, eating mostly crustaceans and other larger microorganisms in their environment. Hydras sting prey with venom stored in nematocysts along its tentacles, which then carry the prey to its mouth. It attaches to substrates by its basal disc at the aboral end of its long, tubular body.

I’ve since found another Hydra in the aquarium so it seems as though they are replicating in this environment.