"It is never sensible to go diving alone, so Dr. Sherman always takes an off-sider (that's Aussie for "pal") with him. A pal is handy for taking those snaps of you showing off your latest catch. And let's face it, if you happen to meet a great white shark, there's a fifty-fifty chance it'll eat your mate and not you!"
This unnamed, second scuba diver was seen in Finding Nemo when Dr. Sherman was seen "rescuing" Nemo after seeing him touch his "butt" (boat) and being yelled at by Marlin. As the father clownfish tries to go after Dr. Sherman, this diver stops him and stuns Marlin by taking his picture with yellow waterproof camera with an "A113" model code label. Unlike Dr. Sherman's scuba suit and mask, which is black with green stripes, their scuba suit and mask is mostly blue with yellow stripes. It is possible that this person is a friend or relative of Dr. Sherman's.