One woman said, "Lucky you. They reckon the sea life is getting filled with plastic but I didn't realise they meant money. Hope there are some out there with $100 bills in them."
Some didn't believe the picture, saying it looked like the note had been tucked inside the fish.
Experts said it was hard to tell if the find was real. Photo / Supplied
Others joked how it would have cost more than that to catch the snapper with fuel and running costs.
Someone said they had found 20 cents in a snapper too.
Dr Richmond Loh, aquatic veterinarian who runs The Fish Doctor, told Yahoo News Australia the note was in the correct organ you'd expect it to be in if swallowed.
"Having said that, pink snappers have slightly downturned mouths (consistent with being bottom feeders), making it less likely that this snapper would meet with a $20 bill that is floating at the water surface, though they are known to come to the water surface at times," he said.
"A $20 note is not a small item that can be easily swallowed by accident, so the snapper would have had to also 'mouth' it (chew and taste) to check if it's something edible using the tastebuds inside its mouth before it would swallow."
