One of the common species on the Similan Islands that many of our guests notice, but is not flashy or portrayed in the movies (like Nemo) are the Cornetfish. These are very long, narrow fish that are also called Arrowfish because of how long and thin they are.
they are no threats to humans and are not actively fished. They also tend to slowly move behind humans while diving or snorkeling, to better use us as camoflauge. Generally around 1 meter in length they are no exactly invisible....until they are pointing right at you!
Then they nearly disappear. Their profile while directly facing you is tiny...just a small dot blending into all the colors and motion of the ocean. This is their predatory adaptation. The more common and more colorful Trumpetfish are close relatives. These can often be seen from the surface while moored over many of the dive sites in the Similan Islands

The Cornetfish is not actively fished for and if caught as by-catch is generally just sent to make fish meal (feeding shrimps).
Just another fish that make up part of the big spectrum of sealife around the Similans.

This video was shot during a nightdive on our Similan Liveaboard. In this particular case the videographer did violate one of the rules of night diving by shining the light directly in the fishes eyes. This is not good for the fish as they can be stunned and/or temporarily blinded.