Fish body color and living environment

Some fish have different colors among different individuals of the same species. The color of sea trout in British rivers is closely related to the surrounding environment. Trout living in river rapids and small water bodies in mountains have many round spots on their bodies; while individuals living in large lakes turn into bright silvery white, and the round spots turn into X-shaped black spots; or a mixture of the two types Trout that inhabit ponds with muddy bottoms, or individuals living in lakes and swamps with muddy bottoms, are darker in color; but individuals living in caves and crevices are almost entirely black; while trout living in lakes with gravel bottoms are darker. Individuals have beautiful colors and lively shapes, similar to those seen in fast-flowing rivers with gravel substrates.

Some fish are the same The body color of an individual changes within a certain range as the background changes. This is a special adaptation of fish to their living environment. This change, depending on the species, will vary in the ability and speed of color change. Groupers living in tropical oceans can quickly change their body color, from black to white, yellow to scarlet, red to light green or rich brown, etc. They can also change many spots, stripes, bands, etc. The lines become bright and dark, and can change into 6 different background colors in a short period of time. The unity of color change and environment makes flounder the strongest and most representative among fish. Flounder can make its body color so similar to the surrounding mud, sand and gravel that unless the fish is moving, it is almost impossible to tell the difference between the fish and the environment. For example, a plaice has obvious orange-red spots on its body surface, but when it swims to the bottom of the water with white pebbles, the red spots turn to white in order to adapt to the environment. Turbot, which lives on the bottom of dirty sand and mud, is usually gray in color, but in an aquarium with sand on the bottom, it turns gray-yellow; but if it is placed in an aquarium with a large pebble bottom, it will produce Yellow spots, these spots are like scattered in a dark mesh.

　Italy Napoleon Aquarium The museum once conducted an experiment on the discoloration of flounder, which was very interesting. The experimental method is to draw black and white squares, black and white circles, etc. on the bottom of a glass dish, and move a plaice from one glass dish to another to make it change color. Usually the color change of flatfish can be achieved in an instant, but the background of this glass dish is not used to the flatfish at first, and it takes about half an hour to complete the color change. We know that fish can quickly strengthen their response to background harmony through exercise, but the range of color change is limited to the colors of ordinary environments such as black, brown, gray and white. A scholar in the United States placed flounder on white, black, gray, brown, blue, green, pink and yellow backgrounds. The flounder can cleverly change to the same color as these backgrounds, but it responds quickly to various colors. different. Changing to red is more difficult than changing other colors. Yellow and brown change at the same speed, while blue and green change take longer and take a long time.

Fish that changes color There are so many categories. Discoloration is mainly controlled by the nervous system and endocrine system, and the specific conditions vary depending on the species. Most fish's color perception of the surrounding environment mainly relies on the head nervous system. Someone once did an experiment, dividing the bottom of the aquarium into two halves, painting two color patterns, or placing substrates of different materials, and then placing the flounder's head aside. The body is on the other side, so the body color of the flounder changes according to the color of the side where the head is.

Fish change color Although the main motivation is to be consistent with the environment, there are other factors at the same time. Just as humans can quickly turn crimson or pale when suddenly stimulated, some discoloration in fish seems to be an impulse of the situation. For example, when a fish is excited when feeding or is suddenly exposed to electric light, it will display certain colors and patterns. When a fish is injured, sick, or due to lack of oxygen in the water or deterioration of water quality, the fish's body color will darken and lose its luster. When fish such as snakehead are shocked by electricity, their body markings will disappear immediately and become pale. The color of fish changes drastically after death.

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