Do you take in donated fish? I have an alligator gar that got to big for my tank.

you will need to call them up for this.

Lmao Alligator gar (Atractosteus spatula) are ray-finned euryhaline fish related to bowfin in the infraclass Holostei (ho'-las-te-i). The fossil record traces their existence to the Early Cretaceous over a hundred million years ago. They are the largest species in the gar family, and among the largest freshwater fishes in North America. Gars are often referred to as "primitive fishes", or "living fossils" because they have retained some morphological characteristics of their earliest ancestors, such as a spiral valve intestine which is also common to the digestive system of sharks, and the ability to breathe both air and water. Their common name was derived from their resemblance to the American alligator, particularly their broad snout and long sharp teeth. Anecdotal evidence in several scientific reports suggest that an alligator gar can grow up to 10 ft (3.0 m) in length and weigh as much as 300 lb (140 kg)

In some cases; but you'll need to call them to find out if your alligator is one of those cases. Otherwise there are alligator farms you can send your alligator to, but i think the closet might be in Florida. Good luck!