Love at first sight
They got to know each other through a mutual acquaintance named Marie Blanton. She's Gunnar's dog mum and a trainer at the rescue centre.
And according to Marie, it was pretty much love at first sight. Talking to the Insider, Marie said:
"When Gunner first went on the docks, I was expecting him to bark, but he did the exact opposite: He just laid down and watched."
"Then every time I would bring Gunner down, Delta was the first dolphin over to the dock. He would bring him his toys to play with him."
The friendship blossomed, and the Retriever started visiting his dolphin buddy a few times each week. And they usually greeted each other with an adorable little kiss!
Unfortunately, Gunnar and Delta don't see each other as much as they used to. Delta is busy teaching centre visitors all about dolphin conservation.
Best friends for life
Meanwhile, Gunnar has got important snuggle duties to fulfil back at the family home.
But like all amazing friendships, the love runs deep between these two. And when they do get to see each other, it's as if Gunnar and Delta were never apart!