When fisherman William Larue spotted a hint of silver shining near the surface of New Caledonia's Toombo Reef, he did not expect to discover a new species of fish (or the cutest one of all time, for that matter).

Image: William Larue/used with permission

The tiny fish (suspected to be a hatchetfish from the family Sternoptychidae) was sent to the laboratory at Secretariat of the Pacific Community (SPC) earlier this year for identification. Hatchetfish usually live at depths between 200 and 2,000 metres, making this fishy find a bizarre one. 

"It is extremely rare to see such specimens at the surface of the water," explains SPC researcher Elodie Vourey. "According to the [fishermen], a school of dolphins was at the site. We hypothesised that as the dolphins were coming up from the deepwater, they pushed this fish to the surface."

After an in-depth study of the mystery fish's shape, colour and the location of its photophores (light-emitting organs thought to help conceal fish from the predators below them), Vourey determined that the specimen was one that had never been seen before.  

A row of purple photophores. Image: Elodie Vourey/used with permission

"This discovery once again demonstrates that there is still much to learn about our marine environment and that many biodiversity treasures are waiting to be found in our waters," says SPCThe French National Museum of Natural History will be conserving the specimen in their collection.

Exciting as this find is, the team needs more than just one specimen to describe a new species officially (which they hope to find during the upcoming mission aboard the research vessel NECTALIS). 

"This expedition was prepared before this discovery," says Vourey. "They will explore the waters offshore of the southern part of New Caledonia in order to better understand the workings of the deep-sea ecosystem ... Maybe (fingers crossed) they will find another specimen of this new species. We hope to write the paper as soon as possible."