One of my dearest old friends, Bertram Hoare, long gone, he'd be 112 years old this year, old-style chalkstream dry fly fisher supreme, had a Springer spaniel named Rajah (so named as a back-handed 'compliment' to the Indian Maharajah to whom he was adviser and Private Secretary when he lived and worked in India as a young man) that was the ultimate fish-retriever.
When I fished with Bertram in the 1980s, when he was in his eighties yet could still outspot and outfish pretty well anyone, Rajah used to sit on the bank having a quiet, doggy nervous-breakdown every time a fish was hooked, even when a fish merely rose to a natural fly many yards away.
"Get him, Rajah." Bertram would say once a day.
And he did, returning the unharmed trout to Bertram's hand.
Got some great photos of the pair of them, in black and white, that I must dig out.