An uncharacteristically flat Carrington, who finished in 1:53.75, was pragmatic about the result in her first race back since August, relishing the increased competition.
"It's always disappointing when you want to be better but Teneale and Aimee are paddling so well and you can't detract from how good they're going," Carrington said.
"It's good to have a hit-out and it also pushes me knowing the spot isn't mine until I prove it."
Carrington qualified for two Olympic spots with her historic world championship 200m-500m double in August, though her selection still needs to be confirmed.
Although this weekend's regatta was the first official selection event of the season, February's national championships and past performances will also be taken into account.
Hatton, who won the world surf ski championships in Tahiti in October, spent two weeks training in Sydney and last week was still ocean racing in Perth. That diet of varied paddling is unlikely to change now.
"We're all coming off heavy base work so you don't have a lot of speed, and everyone's at difference phases but everyone's still fighting it out and to take a win is pretty satisfying, this early on, especially coming off the long ski stuff," she said.
Fisher, who was part of the New Zealand women's K4 boat who also qualified for Rio, completed a dream weekend by taking out the K1 200m final, although Carrington and Hatton didn't race that distance.
She clocked 41.33secs in the sprint, finishing ahead of her three K4 teammates, Caitlin Ryan (42.21), Kayla Imrie (42.86) and Jaimee Lovett (43.31).
Scott Bicknell and Marty McDowell led the charge in the men's ranks, meanwhile, with both paddlers eyeing Olympic qualification through the Oceania championships in February.
Bicknell comfortably won the K1 200m in 35.54secs, ahead of Hawkes Bay clubmate William Wilkins, with North Shore's Jamie Banhidi third. Bicknell then paired with Craig Simpkins to win the K2 200m final from Wilkins and Andrew Roy (Bay of Plenty).
McDowell also showed the benefit of recent training in Sydney with Australian champ Murray Stewart, after failing to secure Olympic qualification at the world championships.