'They are not there to eat us, but sometimes they might take a little bit, like mosquitoes and leeches and other things out there in the environment, ' he said.
Kanizay said on Monday he was soaking his legs at Brighton beach when he felt the creatures attack, causing wounds that would not stop bleeding.
"I collected these odd creatures from the same spot last night by trapping them in a net and standing in the water myself", he told the BBC.
Mr Kanizay returned to the beach on Sunday night with a net filled with raw meat and captured tiny bugs which he believes were responsible.
While still seemingly in pain from the attack, Sam managed a smile as he was released from Dandenong Hospital on Tuesday.
She believes that Sam might have disturbed a feeding group and while he was standing still in the water, assumed the pins and needles he was feeling was numbness in the cold water - but was probably the animals snacking on him.
But Walker-Smith told the ABC's RN Breakfast program the amphipods posed no risk to the public and that it was safe to go back into the water.
"As soon as we wiped them (his legs) down, they kept bleeding", he said. She said amphipod bites were common and "normally you would feel them or brush them off".
"It looked really bad in the photo, his feet looked like they went through a mincer, but it's a superficial injury and more like a graze than anything else". When he came out of the sea he was bleeding profusely from the calves down.
"I would expect and hope he will recover pretty quickly".
While it's likely the sea fleas were the culprit, there's still room for doubt. They took their son to the local hospital, were doctors tried to stem the blood flow.
"He (Kanizay) must have been very, very cold and he wouldn't have felt it", added Weir, who experienced a similar injury on his forehead after a night dive 40 years ago.
"It's great that people are being educated along the way - educated and I guess entertained", Mr Kanizay said.
Last month, a Florida man made headlines for surviving without loss of limbs from a fatal flesh-eating bacteria infection he got while hiking Mount Garfield in New Hampshire.
Associate Professor Reina said sea fleas should not alarm people or deter them from swimming.
"It's not a burrowing animal, it's not a toxic animal, and it just loves eating our flesh", he said.
"They're scavengers who'll clean up dead fish and feed on living tissue", he said.