Curiosities of goldfish – Fish with vibrant colors and a variety of patterns are one of the most outstanding characteristics of the reef ecosystem. In this sense, it is interesting to know that it is proven that these animals are endowed with a well developed vision and an ability to distinguish colors and color patterns.
Progressively, scientific knowledge about visual ability in goldfish continues to increase. This offers some advantages in nature.
1. The color serves to communicate and attract attention
Colors and patterns play an important role in communication within and between species of fish in a reef. The wide variety of color patterns attests to the need for fish to recognize and identify each other in the high density environment of neighbors that the reef represents.
In certain species, males and females have different color patterns. This allows each fish to identify their partner. The distinction between males and females is especially important, for example, during reproduction.
2. Goldfish have their camouflage strategy
It is thought that the wealth of patterns has been selected as an evolutionary advantage. The patterns allow camouflage and masking, which has modified the relationship between predators and prey.
Thus, unusual color patterns such as horizontal and vertical stripes, lines that hide the eye, color patterns that mimic the environment and much more can be observed on a reef.
3. Color as a warning
The color pattern of a poisonous fish communicates a clear message with its mere presence. The colors warn the other fish that both are dangerous.
Warning colors are characteristic of toxic or poisonous fish. Among them are the lionfish (Pterois antennata) with reddish brown stripes, the Fish Fish chest (Cubicus oyster) with blackheads, and many other fish.
It is known that several patterns in harmless goldfish have evolved to simulate patterns of warning. By adopting these patterns the fish disguise themselves and deceive their possible predators. This is known as masking pattern.
The strategy of masking patterns is intended to exploit the color and shape of other fish for the benefit of masking.
4. There is a sex change in fish and is accompanied by a change in color and pattern
More than 500 species of fish are sequential hermaphrodites: This means that they are born from one sex and throughout their life they can change to the opposite sex. Species that change from male to female are called “protrandic” and those that change from female to male are called “protogynous.”
Commonly, these fish live forming a harem in which there is a dominant female, although all are under the care of a male. If the male dies, the dominant female will assume the role of aggressive male.
In a matter of hours, it already shows a change in behavior, courting other females. Then, gradually acquire the traits of the dominant male, The total sex change takes about 10 days.
Usually, fish that change sex also change the colors of your body. For example, Anthias fish – three tails or lorito – being female is orange, and after it changes to a male, its color turns purple.
The change is not only appearance, but undergoes a bodily transformation that includes its reproductive organs. This will produce sperm instead of eggs.
Examples of fish that are sequential hermaphrodites are the clownfish, several species of parrot fish, the cleaning thrush (Labroides dimidiatus) or Bluehead Widow (Thalassoma bifasciatum).
5. Goldfish do not perceive their colors just like us
The natural starting point to understand why fish are colorful is to understand how their eyes work. To fully understand this point, it is necessary to remember that color is an appreciation of the human brain.
In simple terms, light impacts an object that absorbs part of its electromagnetic waves and reflects the others, which reach the human eye. The reflected waves that the human eye captures, is what we call color.
However, the human eye does not see all the waves that make up the light. The range of “visible” light ranges from red to violet. There are waves above the red and below the violet.
The electromagnetic waves that the human eye cannot perceive are made up of infrared and ultraviolet. The spectrum is larger and includes a range of different wavelengths.
Fish, among other living things, can perceive light spectra not visible to humans. Consequently fish have a completely different image of the world around us.
Approximately half of all fish can detect ultraviolet (UV) light. In addition, between 20% and 30% of fish can see UV light as a different color.
For example, damsel fishes – from the pomacentric family – see the visible spectrum and also detect UV light. Since this fish feeds on plankton, and this reflects a lot of light in the UV spectrum, this capacity represents a substantial advantage.
The variety of visual ability depends on the habitat of the fish and the depth gradient where it lives. It is known that large predators tend to be colorblind.
Experts say that before knowing why the fish are brightly colored, it is necessary to find out what color they really are in the eyes of the inhabitants of the marine world.