My little sister has brought home four large-ish tadpoles (there were little black ones and slightly larger brown ones, and she chose to capture the brown ones).

From what I found on the web, it seems like the little black ones were toadpoles, and what we have will turn into frogs. They're in a large jar of bottled water mixed with water and algae from their stream, and the algae has settled to the bottom.

I can't see much in the way of limbs, though there may be little stumps near the rear of one of them.

I want to take the best care of these little guys that I can. I don't want anything to happen to them!

I think it would be best to release them once they're grown, but I don't know how big they should be first, and it's going to be a struggle convincing my sister (and my dad) to let them go, so information on keeping the frogs happy once they're adults would also be appreciated, just in case we need to accommodate them for a little while past their adulthood . . .