Fish Maintain A Social Rank

Do Fish Maintain A Social Rank In Your Tank?

What evidence is there to suggest a social hierarchy among fish?
Will fish in captivity exhibit these behaviors?
How does a fish show dominance?

These behaviors include: Fin display, charging, chasing and biting. When a fish wants to appear fierce, it shows its dorsal fins. This is a sign of threat. Fin display alone can force some fish into submission. Charging involves a slow, yet direct, approach toward another fish. By charging, the dominant fish expresses that it is not afraid to attack. Chasing is basically the same concept. Biting is the actual expression of attack. Biting is the last measure in gaining dominance. All other fish will likely become submissive.

Why do some fish seek dominance?
It is the cornerstone of survival and evolution; survival of the fittest. By gaining dominance it provides an increased access to food and resources. In addition, the dominant member of a school will get preference when it comes to mating; they will be able to choose the best mate. Dominant fish usually become bigger and faster as a result.

Without some sort of dominance hierarchy some species would not last. When the dominant fish goes to choose a mate, he chooses the one most likely to produce the greatest number of strong fish. If it was performed more egalitarian, the genes would not be combined in the most beneficial way.

What signs do submissive fish demonstrate?
Submissive fish are less likely to raise fins or move around. The submissive fish will simply follow the dominant fish. They are more prone to attacks from the dominant fish and outside predators. They tend to always be smaller in size. Submissive fish get the last choice of a mate or have none at all, and they are usually the first to die in the school.

Will fish display this in captivity?
There have been many studies documenting this behavior in captivity. Regardless of being captive or not, fish still have an overwhelming instinct to survive and to procreate. If you have an aquarium you will see the aforementioned signs of dominance.