The 15-year-olds became the first Tigers swimmers on record to share the same podium after taking silver and bronze in Glasgow, with Deffains taking Dodds’ record from him before it was reclaimed in the next heat.
Deffains, who claimed gold in the 1,500m earlier in the week – in a new Island junior record time – clocked 8min 36.39sec for bronze over the shorter distance, with Dodds taking second spot on the podium in 8.34.01.
Salford’s Max Adams claimed gold by just 0.26s.
Tigers coach Nathan Jégou said: ‘This is the first time in our history that we’ve had two swimmers the same age, male or female, on the same podium so it’s massive for the club and for the boys as well. It shows everyone is doing a good job and they’re pushing each other along as training partners.
‘It was particularly nice for Isaac to get on the podium because he’s been held back all week in terms of the number of events he could do. British Swimming only allowed him to do two or three because he’s representing them at the European Championships next week [Open Water], even though he qualified for seven or eight. And he wasn’t allowed to defend his 200m backstroke title from last year.’
Jersey junior Robbie Jones, representing Mount Kelly, won silver in the 200m IM on Saturday and Deffains ended the week with a 14th-place finish in the 200m freestyle.