Couple Find Strange Black "Walking" Fish In New Zealand Bay

People come across odd animals all the time, posting the photographic evidence online and sparking a wave of discussion about what the heck that animal in the pic actually is.
Most of the time these critters end up being nothing more than deformed or otherwise genetically defective, but sometimes their discovery is actually an important biological breakthrough.
A couple in New Zealand found a strange black fish while snorkeling in the Bay of Islands near Auckland, the fish seemingly "walking" along the ocean floor.

They caught the fish and sent it to researcher Andrew Stewart from the Museum of New Zealand Te Papa Tongarewa so he could study it and tell them what they'd found.
Andrew came to the conclusion that the bizarre black fish is actually a rare variation of the striated frogfish, but Andrew was amazed by the fish's jet black coloration considering they're normally brightly colored and boldly striped.

(YouTube Link) 

Now the black sheep of the frogfish world is part of the Te Papa collection, where they'll study it to discover whether the black coloration is an evolutionary adaptation or merely a mutation.