Some ideas for Snaiadi Bugfishes (Arthrognaths).
The main idea is that their lower jaws developed from a pair of pincer-like appendages, which fuse together and creates the form. When they open their mouth, there's a small opening between the middle jaw and the upper jaw, which could take in water for the gills. Their gills are located in the operculum, which also doubles as a body armor. The stomach and heart is also located in this general idea, although the gills are beside the stomach (the stomach is separated from the gills by some flesh). The nervous system consists of a brain, a secondary ganglion, and a spinal cord. The brain and the ganglion are located in the head (the ganglion nearer the 'snout' ). The eyes are directly connected to the brain, and they are like mantis eyes; while the smelling organ and some other sensors in the head area are directly connected to the ganglion. Some bugfish families have multiple eyes, the most being four pairs. The Bugfish has two tounges side by side. The most striking feature is that Bugfishes have three appendages attached to the lower part of the operculum, these could be something between three fins and two claws and a fin. The body-tail part behind the operculum is mostly powerful muscles used to swim. Their reproductive organs are located between the brain and the ganglion, and they lay their eggs in the head area. Some even guard their eggs in the operculum. In males, they spew their sperm from the gap between the middle jaw and the upper jaw.