8.0.4 UPDATE
(Note: Please name this creature with a name tag or it will despawn)
Sturgeon is a small, passive, aquatic, prehistoric creature from the Mesozoic to the modern-day that was added in Build 7.3, the Dinosaur Renaissance update. It is a living fossil fish that spawns naturally in the world but can also be created by the player, similar to the nautilus, alligator gar, and coelacanth. It is around 1 block tall and 3 blocks long, the maximum size for the species in real life. They drop a raw fish when killed. Groups of sturgeon spawn in rivers, replacing the old fictional River Coelacanth subspecies. Right-clicking a sturgeon puts it into your inventory as an item, which can be cooked.
Though they spawn naturally, they can also be created by the player through the culture vat. As they are fish, they hatch from spawn that need to be placed in water.
BEHAVIOR
Sturgeon is an aquatic mob that can spawn naturally in the world. They spawn in rivers and lakes. Since they are passive mobs and do not defend themselves, they are vulnerable to marine predators like mosasaurus and liopleurodon. They can only live underwater; when placed on land, they flop around, dying of suffocation at a rate of one heart per second. Right-clicking catches them, and then you can release them into the water or cook them to eat. They can also ride minecarts.
Sturgeons can breed by laying fish spawn, which needs to be right-clicked in water by the player to hatch. Since they do not have sexes, the amount of nearby sturgeons do not affect the breeding probability.
Like other living fossil mobs, they cannot be tamed, ordered, fed, or aged, given essence of chicken, and do not have genders or moods.