"I've known Polly for years and people don't realise what an accomplished horsewoman she is," he said.
Manning prepared El Pescado to win three races, including two open handicaps, and to finish runner-up to Kawi in the Makfi Challenge Stakes. He was also placed in the Gr.2 Tauranga Stakes and in the Listed Flying Handicap.
He made his final appearance for him when third in Saturday's open mile at Te Rapa.
"It's a bit of a kick in the guts really," Manning said. "We've put a lot of time and effort into the horse and he's won more than $170,000."
Manning said El Pescado wasn't himself during a brief autumn campaign.
"He went off the boil for a couple of starts and he was way below par in the Easter. I had a virus go through the team and while he didn't get it, he was very quiet at the time."
Manning believed the gelding now needed to step up in distance.
"He looks to me like he wants more ground," he said. "He's only had one run at 2000 metres when he finished fifth in the Livamol at Hastings and he should nearly have won that - he got skittled in the run."
- NZ Racing Desk