But now, the Shedd is celebrating her anniversary. Nickel arrived at the Shedd five years ago from the coast of Florida, lucky to be alive after the boating incident.
She was in poor condition, recalled Michelle Sattler, Caribbean Reef Collections Manager.
"She had been hit by a boat propeller, but they did a great job of mending her up and getting her back to the state where we could adopt her at the Shedd Aquarium," she said.
The injury healed, but her shell is still damaged, which causes her to swim in an unusual way-- sort of up floating fanny.
Nickel actually started her rehab 10 years ago. Five years in she came to the Shedd Aquarium, her now permanent home. There she was named Nickel, and for a very good reason.
"During Nickel's physical we realized during the x-rays that she had a coin lodged in her esophagus," said Sattler. "And this coin actually turned out to be a nickel."
She became "Nickel" and has been healthy ever since.
Wednesday morning Nickel got a special treat straight from her favorite underwater world five-star restaurant.
"She's going to get a large squid stuffed with fish diet wrapped in anoori, and the whole thing is wrapped anoori again... Sushi," said Sattler.
Nickel obviously thinks this is much more than just a two-bit meal. This is heaven for a species that goes back about 150 million years.
That's why the Shedd loves her so much. It's like touching and feeding a swimming dinosaur.