Making friends is an important part of life for humans, but do fish also form social bonds and friendships? Research suggests that some species of fish do exhibit behaviors associated with friendship such as cooperation, reconciliation, and selective social bonds. In this article, we’ll explore the evidence that fish can make friends.
Do fish interact socially?
In order for fish to have friends, they need to interact socially and recognize other individuals. Scientists used to believe that fish lived fairly solitary lives, coming together only to mate or feed. However, we now know that many species of fish travel together, communicate with each other, and develop social preferences and bonds.
Grouping behaviors like schooling and shoaling demonstrate that fish are social creatures. But fish go beyond just grouping together for defense or finding food. Studies have found that some fish can recognize individual tank mates using visual cues and remember them even after long separations. Fish also use a range of signals like body color changes, fin movements, and chemical cues to communicate information to each other.
Do fish cooperate and reconcile?
Cooperating with friends and reconciling after conflicts are hallmarks of human friendships. Some fish species display similar cooperative and reconciliatory behaviors.
Cooperation among fish has been observed in predator inspections, territory defense, and hunting. Predator inspection involves a pair of fish cautiously approaching a potential threat while taking turns moving forward. This allows them to share risk and acquire information. Cooperative hunting, seen in species like coral grouper and rabbitfish, enables the fish to take down larger prey through teamwork.
Makeup behaviors like tail wagging after aggressive acts have been interpreted as reconciliation in fish. Reconciling after conflicts helps maintain social bonds, so this suggests relationships exist between fish beyond just convenience.
| Species | Cooperative Behaviors |
|---|---|
| Lemon Sharks | Group hunting |
| Groupers | Cooperative hunting with giant moray eels |
| Rabbitfish | Predator inspections and group hunting |
Do fish form social bonds and preferences?
There is evidence that some fish do form selective, individualized bonds and prefer familiar fish over strangers. Guppies and damselfish can recognize familiar individuals and demonstrate social preference for fish they know versus strangers.
Scientists tested this by allowing fish to choose between a compartment with familiar fish or one with unknown fish. Given the choice, fish spent more time with the familiar fish.
Being separated from a bonding partner seems to negatively impact some fish as well. Separation anxiety is a sign of an emotional bond between friends. Archerfish that were separated from bonding partners showed signs of anxiety and took more risks to try to reunite.
Factors influencing fish social bonds
Several factors influence which fish are likely to form strong social connections:
- Group size – Fish in smaller groups form stronger social bonds.
- Environment – Fish in riskier habitats with more predators rely more on social partners.
- Cognitive ability – Fish with higher intelligence are better able to recognize individuals.
- Feeding habits – Fish that hunt cooperatively in pairs form partner preferences.
Examples of fish friendships
Here are some examples of fish friendships and social bonding that researchers have documented:
Cichlids
Cichlids are highly social fish that live in groups and develop relationships. Researchers found that cichlids prefer to spend time near familiar fish over unknown fish. When cichlids were separated from their tank mates, they acted agitated and aggressive when reunited, but quickly reconciled.
Guppies
Male guppies form “companionships” with other males that help them attract better mates. They cooperate by courting females together. The presence of a friend boosts male guppies’ confidence and chances of mating success compared to loners.
Electric fish
Electric fish communicate using electrical pulses. Mormyrid fish that live together start to mimic the pulse timing of others. This synchronization suggests bonding and mutual adjustment between fish friends.
Sharks
Some sharks, like lemon sharks and bonnethead sharks, prefer to hang out with specific social partners to hunt and swim together. Sharks can recognize friends through chemical and visual cues. They form long-term social preferences for specific individuals.
Do fish feel grief when a friend dies?
The loss of a bonding partner is another situation that can provide clues into the mental state of fish. There are anecdotal reports of fish appearing to grieve dead companions by remaining close to the body or lying on the bottom of the tank.
Scientists conducted an experiment on archerfish to test this. They compared the reactions of archerfish when their partner was removed from the tank versus when their partner was fed to a predator. The archerfish showed signs of behavioral depression only when they witnessed their partner eaten, not just removed.
This provides some evidence that fish may feel grief related to the permanent loss of their social bond, although more research is needed.
Conclusion
So do fish make friends? The evidence suggests that yes, some fish do form individualized social bonds that go beyond just schooling together or shoaling. Cooperative behaviors, reconciliation, partner preferences, separation anxiety, and grieving all point to fish having emotional connections to specific individuals, not just their species.
However, fish social behavior and cognition vary greatly between species. Schooling fish like herrings and minnows are unlikely to have the cognitive capacity for complex social bonding. But research shows fish like wrasses, cichlids, guppies, and shark species that live in smaller social groups do recognize and form preferential relationships with other individuals.
So while not all fish make friends, there is clear evidence that some intelligent, social fish species can develop bonds and friendships with individual tank mates, cooperating and communicating to maintain their relationships.