Like Nemo, tropical fish look out of place in southern waters, thousands of kilometres from their usual homes on the Great Barrier Reef on Queensland's eastern coast or at Ningaloo Reef, off Western Australia's coastline.
Their vivid colours give them away.
These usually northern fishes have been seen as far down the eastern states as Narooma on the New South Wales south coast, according to boat skipper and citizen scientist Georgia Poyner.
Marine biologist Dr Adriana Verges says the Solitary Islands have an extraordinary mixture of tropical and temperate marine species. (Supplied: John Turnbull/#marineexplorer, Source: ABC News)
"They're the fish that are quite often bright blues and yellows. And they stand out a fair bit from the other local species," Ms Poyner said.
When Ms Poyner is not skippering game-fishing charters, she is often diving in the waters around Narooma.
There, she's noticed the arrival of more and more tropical fish.
Continue reading on the ABC News site: Hungry tropical fish, sea urchins marching south as kelp forests disappear