His father, Jarrod Kanizay, said his son was completely calm and was not in any pain. "There was a massive pool of blood on the floor (at the hospital)".
The crustaceans are related to shrimp and lobster and there are about 10,000 species of them, he said.
There are still a few soft spots on Sam Kanizay's legs where sea lice ripped into his flesh but the Melbourne teenager is nearly ready to leave hospital. The bites seemed as if he had been pricked many times with a pin or needle.
"I've never seen anything like this", one marine expert told a local TV program.
Reina told news.com.au that sea lice don't generally travel in a large group, but that once a small number drew blood, it would have attracted all the others.
"They are very good at finding food", he said.
"These little things really love meat", he said.
"I would expect and hope he will recover pretty quickly".
Armed with a fishing net and a slab of fresh meat he headed back the beach and captured hundreds of the creatures he believes were responsible.
While it's likely the sea fleas were the culprit, there's still room for doubt.
Photos show Kanizay was profusely bleeding from his calves down, in a garish downpour that puddled around his feet.
"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.
They discovered thousands of tiny bites on the teen's legs, nearly as if he had been pricked with a pin repeatedly.
Mr Poore said he was doubtful that this was a particularly aggressive strain of sea lice but suspected that there may be greater numbers in the area than normal - something that may be caused if a lot of dead fish were in the area.
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.
"They are just little animals following their natural instinct and eating what they thought was a free meal", he said. The name is broadly used to describe small external, parasitic crustaceans that feed on skin and blood or the larvae of jellyfish.
"The situation is really unusual and I don't think it's something people should be concerned about".