Pascoe, 20, was delighted to snare the 50m freestyle world mark, which is an Olympic event where she won the silver medal in London behind Canadian rival Summer Mortimer. She clocked 28.01 to go under the world mark by 0.2s.
"I've been waiting for that one for two years. It was held by my main rival Summer (Mortimer) so it's nice to say that Summer's out and winter's in."
"It's a personal best for me and my times are up at world record standard so that is what I try to do every time I get in the pool. That was a huge personal best and I came out with a world record as well which was a bonus."
Fisher, 20, from Wellington's Capital Club, took more than 10 seconds off the world record in the 200m butterfly. She clocked 2:50.93 to smash the previous mark which stood at 3:01.10.
Fisher said she had concentrated on butterfly following the Paralympics which has set her up for her world record blitz this week.
"It's good now that our world championships are aligned to the FINA world championships that means we can come here to qualify," Fisher said.
Kean solidified his place on the world championship team with a second qualifying swim in the 50m backstroke. He was just 0.2s outside the national record held by Daniel Bell and was pleased to add another event to his schedule in Barcelona.
"It's given me an opportunity to swim another race at world champs so I'm pleased about that because I like to continuously push myself throughout the competition and keep the systems going," Kean said.
The Commonwealth Games silver medallist spent several weeks at a high altitude camp in Sierra Nevada in February working on his fitness levels so was happy with his sprinting performance ahead of his specialist 200m event.
"It's nice to see some speed come out of that before the 200m tomorrow (Thursday)."
Lee, 20, clocked a significant personal best of 2:12.58 to win the 200m butterfly in emphatic fashion and was more than a second under the FINA B standard, while Donaldson from Whangaparaoa won the 200m individual medley in 2:01.60 which was also a big personal best under the FINA B standard.
In other final swims tonight Becky Dooley (Jasi) edged out Natasha Lloyd (North Canterbury) by 1/100th of a second to win the 50m breaststroke and 13 year old Hawkes Bay swimmer Bobbi Gichard added the 50m backstroke title to the 100m backstroke she won earlier in the meet.
Hayley Palmer defended her 50m freestyle title in 25.56 which was just outside the qualifying standard, pipping clubmate Samantha Richter by 3/100ths of a second, while fellow Olympian Matt Stanley (North Shore) got up to win the 100m freestyle in 50.31 ahead of sprinter Cameron Simpson (Templeton) to add to his win in the 200m freestyle.
In the finals for Athletes with Disability, Daniel Holt (North Shore) won the 50m freestyle multi-class national title in 25.79, Pascoe's world record earned her the 50m freestyle title, Australian Michael Anderson took the visitor's gold ahead of Jesse Reynolds (Fairfield) in the 100m backstroke and Tayla Clement (North Shore) won the 400m freestyle.
The championships continue until Friday.
Results, day 4:
Women 50m breaststroke: Beckie Dooley (Jasi) 33.26, 1; Natasha Lloyd (North Canterbury) 33.27, 2; Abbie Johnston (AquaGym) 33.32, 3.
Men 50m backstroke: Gareth Kean (Capital) 25.42, 1 (World champs Qualifying); Kurt Bassett (Laser Mt Eden) 25.94, 2; Kurt Crosland (Neptune) 26.19, 3.
Women 50m backstroke: Bobbi Gichard (Greendale) 29.51, 1; Kate Godfrey (Neptune) 29.92, 2; Rima Williams (Laser Mt Eden) 29.94, 3.
Men 50m freestyle AWD Multi-Class (adjusted): Daniel Holt (North Shore) 25.79, 1; Blake Cochrane (AUS) 27.01 (visitor silver); Daniel Gaualofa (Bay of Islands) 28.02, 2; Rick Pendleton (AUS) 27.01, (visitor bronze); Jesse Reynolds (Fairfield) 29.55, 3.
Women 50m freestyle AWD Multi-Class (adjusted): Sophie Pascoe (QEII) 28.08, 1 (World Record); Mary Fisher (Capital) 31.66, 2; Nikita Howarth (Cambridge) 36.77, 3.
Women 50m freestyle: Men 100m freestyle: Hayley Palmer (North Shore) 25.56, 1; Samantha Richter (North Shore) 25.59, 2; Sophia Batchelor (AquaGym) 26.17, 3.
Women 200m butterfly: Samantha Lee (Capital) 2:12.58, 1; Helena Gasson (Thames) 2:16.28, 2; Ali Clareburt (Capital) 2:16.55, 3.
Men 200m individual medley: Mitchell Donaldson (North Shore) 2:01.60, 1; Bradlee (Ashby (Fairfield) 2:04.39, 2; Kurt Crosland (Neptune) 2:04.43, 3.
Men 100m backstroke AWD Multi-Class: Michael Anderson (AUS) 1:02.99 (visitor's gold); Jesse Reynolds (Fairfield) 1:10.75, 1; Daniel Gaualofa (Bay of Islands) 1:15.01, 2; Christopher Arbuthnott (Icebreaker Aquatics) 1:26.90, 3.
Women 400m freestyle AWD Multi-Class: Tayla Clement (North Shore) 5:35.10, 1; Olivia Hay (Whakatane) 6:53.25, 2.
