Like any other animal, fish have a lot to say. Unlike the other pets in your home, however, their way of communicating is not nearly as vocal.
While pet fish can use sound to communicate, it’s not something we pick up on easily. Instead, it’s easier to see their use of body language and tactile communication.
Keep reading to learn more about how fish communicate with each other, both in the tank and in the wild!
Why Fish Need to Communicate
Because scientists are new to studying the sounds that fish make and putting together fish sounds libraries, there’s no established dictionary of the language of marine life. Even within their physical displays and vocalizations, fish are trying to say quite a bit and the information often overlaps.
Fish need to communicate:
- To find suitable mates
- To warn their school about dangers
- To indicate where food is
- To fend off predators
- To establish dominance
The method of communication varies from species to species. Deep-sea fish will not be as dependent on visual cues, while smaller fish can make big noises to scare away predators, but every fish finds a way to “speak” their mind.
Body Language, Colors, and Patterns
Like many other animals, fish rely on body language and physical signs to get their point across. Body language is so universal that it can even let us humans know something as significant as our fish being unhappy.
Something as simple as posturing can be more effective than a thousand words, and you may have seen the fish in your tank doing things like:
- Flaring fins aggressively
- Shying away from other fish
- Dancing for the opposite gender
Some species of fish, like male guppies, become brighter and more vibrant when seeking out mates. Others, like groupers, can alter their colors to let other fish know they’re willing to mate.
Flashing bright colors can also warn off other fish, or even attract prey. Fish from the depth may generate light from their organs in a biological reaction called bioluminescence. This light allows them to communicate in an area where visibility is even lower than shallow water without relying on sound.
Vocalizations and Hydrodynamic Sounds
Light may travel faster than sound, but visual cues break up easily within the water. For this reason, an estimated two-thirds of fish communicate using sound underwater.
This is more obvious if you’re in the open ocean than if you’re sitting a few feet away from your tank, but odds are your pet fish are also using sound to communicate with their tank mates. Most scientists describe these sounds as clicks, grunts, plops, and screeches, with the sound made depending on the fish and what they’re trying to say.
Using technology developed during WWII to detect submarines, scientists can now listen in on the conversations fish have through the dense water. Some, like damselfish, make grinding sounds with their teeth to warn off predators. Others, like herrings, use their digestive tract to expel gas (although scientists are not sure what exactly these noises mean).
Sound is a more solid method of communication in the water that often warps visual cues. Most sounds are inaudible to humans, but your fish’s ears know exactly what they are saying.
Tactile Communication
Tactile communication includes all forms of touch. The fish in your tank may sidle up next to each other for comfort or to court, or you may need to keep an eye out for more serious acts of aggression.
Worrisome tactile communication for fish often includes:
- Fin nipping
- Mouth locking
- Charging and ramming
- Head bumping
Physical fights are uncommon, but they occur whenever fish need to establish dominance or settle disputes. In most cases, fish are more inclined to put on physical displays instead of putting their body in danger.
Electrical Signals
Fish that can generate electric fields, like electric eels and stargazers, use this capability to not only stun their prey but communicate with other electric organ fish. While most places will not allow you to keep these fish as pets, it’s still interesting to learn about their unique communication abilities.
The specialized electric organs of these fish are made up of electrolytes that are specialized to create electric fields that they use to search for prey and defend themselves. Because they can also detect these electric fields, they’re also useful for courtship behaviors and other communication within their species.
