Releasing it was the right thing to do. You can enjoy observing it in the wild, not just captivity.

If you are going to pull in a wild species, it's best to do so responsibly and not just because it turned up. Make sure it's legal where you are, make sure you have a habitat & food ready to go, make sure you're willing to care for it for the rest of it's life, make sure you're removing from a thriving population, and collect the youngest possible to minimize your impact (eggs/tadpoles preferred).

An exception would be those invasive Cubans... I believe they're legal to keep in Florida (but check on that!) and no one would complain if you remove a Cuban or two from the breeding population. But again, make sure you're well read on what their care entails.