Can you give me some tips on collecting hydra

Many years ago I got some water from a pond where I used to live and the glass aquarium walls had lots of hydra.
I tried a place near me last summer and found nothing.
I live in CT and would like to try again when the water gets warmer.

Best way to find them is to gather vegetation in shallow water and place it in the aquarium. Hydra are almost always attached to a surface, not free swimming.