My first encounter with the butterfly fish was in a laboratory during a summer seminar. In a jar filled with formaldehyde lay a beautiful fish, decorated in amazing colors, its elegant display of color frozen in time forever.

Until that encounter, I never knew that butterflies also existed in water, but its colors revealed the fact that they are named after terrestrial butterflies.
Terrestrial butterflies have a short life span, and their breeding only continues for one season – sometimes, with casual partners, and other times in mass orgies with millions of other participants, or more.
This is where there is no correlation, in fact quite the opposite, between butterflies above, and below water.
Butterfly fish establish long term relationships, usually for most of their lives. The couples look after each other, and do not change partners for their entire life. Long term commitment is the key to living together, helping each other to survive on the reef for many years. Breeding only takes place with the same partner every year, although sometimes the fish change their sex, and breed as opposites.
The butterfly fish family is undoubtedly one of the most beautiful and colorful fish families, with a flattened body structure that is perfectly adapted to their coral reef living environment.
Reefs function as a spawning ground for the thousands of animals that live in this environment for most of their lives. Their flattened bodies enhance their sharp movements, and delicate maneuvering between the coral, flapping their relatively large fins to fade between, and above the coral in their search for food. Their color, plus the manner in which they flap their fins, and their darting movements from place to place, are reminiscent of both the color, and reveling movements of terrestrial butterflies.
Their food consists of crustaceans, worms, mollusks, anemones, and coral, which is the most important in order to understand the butterfly fish’s existence on the reef. The butterfly fish is able to successfully eat coral by using its small round mouth, situated at the end of a type of short trunk. The butterfly fish bites the polyps upon which it actually creates its resting place on the coral.
There are 114 species in the butterfly fish family, 14 of them can be found in the Gulf of Eilat, 7 of them are indigenous (live in a certain region) to this area. The butterfly fish usually socialize on the reef as a couple, or sometimes as an individual. The butterfly fish can be observed on the reef throughout their life: maturing, eating, sleeping, defending, courting, and breeding – which is as integral part of reef living. Besides the coral the butterfly fish also feed on sea anemones, during which you can observe the cat and mouse games in which they are involved. The anemone lives together with the sea anemone, and is responsible for protecting it from predators – the butterfly fish.
The butterfly fish’s colorful patterns drive the anemone fish crazy, causing them to attack the hungry invader. Experiments have proved that there is a connection between the butterfly fish’s show of color, and the anemone’s behavior, regardless of shape. We, as scuba divers diving along the reef, are also used to the harassing actions pursued by sea anemones in defense of their hosts. Another phenomenon that exists among both terrestrial and marine butterflies is the use of their color patterns to camouflage the eye area, and to create a “false eye”. The butterfly fish are not equipped with special defensive measures (speed, armor, poisonous spikes, etc.). However, through the use of color, and sophistication, the butterfly fish succeeds in being deceptive, and blending in with its colorful environment. The eye is the key to survival, or rather hiding the eye, by creating stripes, and stains around the eye region in order to camouflage it, and usually the eye participates in the deception with the colored patterns that are formed on the eye.
Predators usually attack their victims’ heads, as a head injury is supposed to paralyze its ability to defend itself, and escape. The predator focuses its attack on the eye but this is not straightforward when it comes to butterfly fish. Trying to locate the eye / head area causes the predator to delay its attack, giving the victim sufficient time to avert the attack and escape.
Another method of deceiving predators is by using a false eye, creating an image of an eye in the rear tail, or fin section which succeeds in confusing the predator. This confusion causes the predator to focus its attacks on less vulnerable areas where the healing process is much faster, enabling the fish to survive its injury and heal – being bitten on the tail is preferable to being bitten in the head. When a spouse is injured, one notices the devotion and commitment the butterfly fish couple have towards each other. During the injury period the spouse will guard, and protect its partner, and its territory.

Author: Aviv Levy – Scientific Manager, Underwater Marine Observatory Park

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