"I'm not saying the kids aren't prepared to work hard, but they're not prepared to wait for the weather," he said. "We went to England and waited four years for the perfect day - and managed to break five world records in 28 hours. Three of them still stand to this day, so we must have done something right."
Rush is also one of only two people to complete a double crossing of Cook Strait, which he achieved in 1984. In the 15 years Rush has been coaching other long-distance swimmers, he said he hadn't come across anyone who could beat his Cook Strait record.
"I'd love for someone to break the records and I'd love to be involved in getting someone to break the record," he said. "I've helped a lot of people try to break them and the bottom line is they're not bloody good enough. That proves to me that, possibly, we were pretty bloody good.
"Now it seems quite surreal, three ways across the English Channel, two-and-a-half ways across Cook Strait. I think, 'did I really do that?'
"The records still stand and the years march on but it does become very . . . surreal probably is a good word."
Rush retired from swimming in 1989, admitting he was physically and mentally spent but he still threw himself straight into firefighting in the hopes of finding a fulfilling career.
"I applied for the fire brigade and they took me first time, which was very fortunate, and 27 years later I'm still there."
The borderline "obsession" he had for swimming set Rush up well for the intensity of firefighting, he said.
"Nothing is as hard as swimming at 5km/h for 28 hours, so anything you do in life, you've got great stickability."
Rush was convicted for drink driving in 2013 - the fourth time he had been caught driving drunk, although there was a gap of almost 20 years between his third and fourth offences.
Rush said he "hugely regretted" his actions and conceded it had tarnished his reputation somewhat. "I should never have done it."
The silver lining of the 2013 conviction was his community service for the Mary Potter Hospice, which he remains involved with today.
"I did my time and some good has come out of it in that the hospice gardens look pretty bloody good now."
Another regret Rush has is not attempting a fourth crossing of the English Channel in 1987.
"To this day, [I think] we should have got off our butts no matter how tired we were and at least given it a go. [It] haunts me now."
Overall, however, Rush said he counted himself lucky to have lived the life he has.
"I've been very, very fortunate."