The hydra's tentacles are equipped with nematocysts and/or batteries of stinging capsules with stinging threads which the hydra swiftly shoots towards any prey swimming past it. In order to move about on the object supporting it, such as a plant, it slowly glides along on its basal disc. If it's in a rush, it quickly advances via a series of somersaults. Dang, what is this, microscopic gymnastics? Ha!
The hydra can also contract completely, into a perfect round ball, at times, then resume back to its extended shape.
What does it consume? Its diet includes various insect grubs, planktonic microscopic organisms, water fleas, recently hatched tiny fry from small fishes, etc.
The victim is paralyzed by the poison from the nematocysts, allowing the hydra to push its prey into its mouth which is located at the center of its circlet tentacles.
Reproduction occurs sexually and by budding.
Hydras are well known for their ability to regenerate as they are capable of regeneration in an endless fashion, it seems. Going by what I have read in the past, their powers of regeneration surpass those of any other member of the animal kingdom. Hey, this reminds me of a blog post I wrote a while back, on another website, entitled "The Immortal Jellyfish – Turritopsis nutricula" - except I spoke about transdifferentiation there, instead of regeneration, but they are similar to each other, in their own special little unique way...
In 1740, the naturalist Trembley of Geneva demonstrated that a hydra cut into pieces produced as many new hydras as there were pieces; in other words, a single hydra cut into 30 fragments gave rise to 30 new hydras - all identical to the original specimen - wow!
Here's a couple images of this peculiar creature, below:
---End of Post "Freshwater Hydra - Capable of Endless Regeneration"