Toadfish

The toadfish is a bottom-living species of fish divided in three groups: oyster toadfish (found in North America), venomous toadfish (found in Western Atlantic Ocean) and midshipmen (Eastern Pacific Ocean).
The venomous toadfish has a dorsal spine situated on each operacle which is connected to the venom glands.
Some species of plainfin midshipman are also special in their own way: they are bioluminescent. They are usually luminescent during courtship but can use it also as a predator avoidance.
An interesting fact is that the toadfish male has an ingenious method for attracting females. First they make a nest, then they contract the muscles on their swim bladder and they start to sing in order to attract a female to their nest. After the female lays her eggs, she retreats on the bottom of the water, leaving the job of protecting the nest to the male.