Can I substitute blackbelly rosefish for spiny lobster?

Can blackbelly rosefish ("cantarilho" in Portuguese) or HELICOLENUS DACTYLOPTERUS, a fish, be considered a substitute of spiny lobster ("lagosta" in Portuguese), a crustacean?

Some people say, after cooking a seafood rice with both, you can't differentiate the fish (fish loin only) from the lobster anymore.

Since the price for lobster is significantly higher than for the fish, I wonder how to detect if it was cooked with crustacean only, or was "stretched" with blackbelly rosefish?

blackbelly rosefish
^{source wikipedia.org}

spiny lobster
^{source mundoecologia.com.br}

Best Answer

What's your goal? Both can make an excellent base for a seafood based rice dish. In a side by side, I bet you would be able to tell the difference. If you are trying to do this surreptitiously, maybe not a good idea. More importantly, does it matter? Why not just make blackbelly roefish rice with broth...call it blackbelly roefish rice with broth...make it delicious, and enjoy? If you are suspicious that you were tricked, maybe ask the chef.