How Do Fish Communicate with Each Other? Do They Have a Language? Through research, scientists have suggested that most fish species possess a form of “observational language”. 
Fish swim back and forth in the water all day, learning about each other through their shapes and external expressions. Not only that, but fish also communicate the locations of food and threats; different species of fish exhibit various ways to signal danger to others.
Fish have a form of “acoustic language”. Thanks to their unique vocal cords, they can produce vibrations, calls, cries, and other sounds. These sounds are inaudible to us as they cannot travel from water to air. For example, the sound made by goldfish resembles that of a frog, while pufferfish produce sounds similar to a dog barking.
Additionally, fish employ “chemical language”, relying on their sense of smell. When a leading fish secretes a slime from its skin, the other fish in the school will immediately disperse in all directions upon detecting the scent. This rule is quite simple; through smell, fish can sense the presence of nearby predators.
Some species of deep-water fish also communicate with each other through electrical pulses.
