The newest animal star at Chicago’s Shedd Aquarium is named Marlin — and he's a dog.

The 2-year-old chocolate Labrador mix is the aquarium’s fourth shelter dog, and he will work as a canine ambassador, greeting visitors and warming up the crowd during the "One World" aquatics show.

Marlin was adopted from Chicago Canine Rescue in December and will be making his aquarium debut this spring.

His first home was in Oklahoma, but the active 70-pound puppy was more than his owner could handle and he was returned to the rescue. That's when Shedd's training team adopted him and gave Marlin his forever home.

Shedd Aquarium canine ambassadorsNow Marlin spends his days playing with Shedd's three other rescue dogs: Bruce the pit bull mix, Dory the shepherd mix and Coral an Airedale mix (pictured right).

All the dogs are named after characters from the movie "Finding Nemo."

Marlin is also undergoing positive-reinforcement training to prepare him for his work as a canine ambassador.

The aquarium says the dogs show off the results of the "Shedd Way" of training — the same training given to its marine animals — and demonstrate how people can develop positive relationships with animals.

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Laura Moss writes about a variety of topics with a focus on animals, science, language and culture. But she mostly writes about cats.

Shedd Aquarium's newest addition is ... a dog?
Marlin, a 2-year-old rescue dog, is being trained to be the Chicago aquarium's newest canine ambassador.