Is alligator or crocodile meat halal?

Why this question comes up

Alligator is served in parts of the southern USA, like Louisiana and Florida (fried alligator bites, gator gumbo), and crocodile meat is sold in some specialty shops in Europe and Australia. Converts who grew up with it, or tourists who see it on a menu, naturally wonder where it fits.

The case for avoiding it

The Prophet ﷺ said, "Every predator with fangs is forbidden to eat" (Sahih Muslim 1933). Crocodiles and alligators hunt with their teeth, so the majority of scholars apply this hadith to them. They also point out that these animals are amphibious: they breathe air and spend much of their time on land, so they aren't simply "sea creatures" that are halal without slaughter. Imam Ahmad and many Shafi'i scholars explicitly listed the crocodile among forbidden animals. The Hanafi school is the strictest overall on water animals, allowing only fish.

The case for allowing it

The Maliki school allows almost everything that lives in water, based on the verse:

The Prophet ﷺ also said about the sea, "Its water is pure and its dead are lawful" (Sunan Abi Dawud 83). Malikis count the crocodile as a water animal covered by these texts, and some later Shafi'i scholars agreed with them. For how this works with shrimp and other water animals, see Can I eat shrimp and other seafood?

What should a new Muslim do?

Since most scholars forbid it and alligator is hardly an everyday food, the safest choice is simply to skip it. If you follow the Maliki school, you have a recognized view to lean on, but there's no need to argue with anyone about it. The same debate applies to frogs and snails; see Can I eat snails and frog legs as a Muslim? For the general rules, see What can Muslims eat?