Macro shot a Short Head Seahorse or Hippocampus breviceps.
It is a small sea horse with a short snout that well-camouflaged.

The sea horse picture on the seaweeds was taken on a night dive in Edithburgh, York Peninsula, South Australia.

The camera I use is Canon 7D Mark II, Nauticam housing NA-7DMKII, Canon EF 60mm f2.8L macro IS USM, 2x Inon Z-240, RGBlue System 02.
F-stop: f/18, Exposure time: 1/50 sec, ISO speed: ISO 320.

The image was post-processed using Adobe Photoshop (Beta) 25.4.0 to remove some floating particles in the water and on the seaweeds.
Adjusted the brightness, contrast, colour balance, exposure, curve and vibrance.