If they are tadpoles, get a big tub and fill it with water. Put it in the shade. Put a branch on something in it in case something falls in or a frog wants to leave. If you are on city water I don't know what to do about the chlorine or whatever. I have tadpoles in stock tanks. The water is nasty and hot but some of them lived because I still have them. The transition to little frogs must be hazardous because I have found dead ones before that were little frogs with the tail nub. I don't know if they can't get enough food or if it is just a stressful time. I am boiling chicken thighs and Annie the blind dog is trying to boss me around.

About the chlorine in tap water, when I make compost tea or any other tea for the gardens, I let the water set in an open bucket overnight then use it. Got that tip from Soil & Compost Forum.
Sunny