Paralympic swimmer Jim Anderson claimed his second silver and fourth medal of the Games in the 50m backstroke.
Anderson, 45, who won four golds in Athens, adds to his silver and bronze after trailing by just over one second.
Robert Welbourn swam a brilliant 400m freestyle, but had to settle for second behind Brazil's Andre Brasil.
Fran Williamson clinched GB's third silver in her women's 50m backstroke final, while Natalie Jones added bronze in the women's 50m freestyle final.
Williamson, who had been second quickest in the S3 qualification, finished in a time of one minute 6.07secs, seven seconds behind world record holder Pin Xiu Yip of Singapore, for her second silver of the Games.
Jones had been tipped to add to GB's gold medal tally in her one-length final, but was beaten by the Netherlands' Mirjam de Koning-Peper, who set a new world record in 35.60secs, and Mexico's Doramitzi Gonzalez.
Team-mate Eleanor Simmonds finished in fifth while Liz Johnson came in eighth.
Welbourn, 21 from Lincolnshire, admitted he was a little disappointed having set a new European and British record in 4:07.61s.
606: DEBATE"It was a massive best time so I can't really complain," he said. "I was hurting so much on the way back, but I am still happy."
Danielle Watts finished seventh in the women's S2 50m backstroke final, while Anthony Stephens came sixth in the men's S5 50m freestyle final, won by Dmytro Kryzhanovskyy from the Ukraine.
Rhiannon Henry set a new British record in the women's 50m freestyle (S13) final, but the Canada-based swimmer finished seventh in a time of 28.59secs.
The British 4x100m Medley relay quartet (34 points) of Sam Hynd, Sean Fraser, David Roberts and Welborn finished in fifth place as Australia smashed almost 11 seconds off the world record with a time of four minutes 11.90secs.
Sascha Kindred and Matt Whorwood failed to reach the men's S6 event final.
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