Alligators, not crocodiles. Crocodiles would be stupendously to do this with; alligators are much less aggressive.
This thing operated for nearly 50 years, from 1907 to 1953. I couldn't find a single report of any incidents of people being hurt by the alligators; it only shut down because attendance had dropped to fewer than 50,000 annually.
I an frankly a little surprised; I thought for sure it got shut down because it alligators ate one to many kids... or pets. People brought their dogs. But, apparently, well-fed alligators are pretty docile unless you make them feel threatened, and the domestic bred ones were used to people handling them from babies.
They're still reptiles, and crocodilians to boot; this whole endeavor sounds batshit to me. But 50 years with a yearly attendance of more than 50,000 people is a lot of evidence.