The Great Barrier Reef.
The word is Marlin not Merlin. They are a "Pelagic" fish of the Ocean and some of the greatest and well known places for fishing for them are on and around the Australian Great Barrier Reef.
atoll
Atoll
The word that comes after "reed" in the dictionary is typically "reef."
Coral is the word you are looking for.
An Australian dog that is also a five-letter word is a Dingo.
The proper noun Great Barrier Reef is a concrete noun, a word for a physical thing.
Aussie
emu
roof, reef, riff, ruff
tuckerbag
Dingo