The blind form also has an increased olfactory bulb size which increases the fish’s sense of smell. They use highly developed lateral lines along their body to detect movement. It prefers to swim alone unless they are breeding. The blind form is the calmer, more peaceful sibling. The surface-dwellers live in large groups that tackle predators collectively. The tetra may target other species’ young. They are seen as potential problems in areas where they are not native. The surface-dweller is an aggressive predator. The two forms have evolved to hunt differently too. They can navigate and map out their habitat. These fish have developed large jaws, additional teeth, and an increased number of taste buds to help them feed. Surface tetras want swift-moving water with significant outflow while the blind tetra lives in calmer waters. The surface-dwelling tetra lives in large schools of several hundred fish while the blind tetra prefers to be more solitary. Many places see a school of surface-dwelling Mexican Tetras right outside of the blind tetras’ caves. The blind tetra is only found in caves or other dark areas. The surface-dwelling Mexican Tetra live in a wide range of sunny rivers, tributaries, and reservoirs throughout the southern part of the United States and down into Mexico. Mexican Tetras do not do well in cold climates and will migrate to warmer climates during the winter months. They are in severe decline in New Mexico and are considered endangered in that state. Some accidental introductions have meant schools of these fish can be found in Arizona, Oklahoma, and Louisiana.
The surface-dwelling Mexican Tetra is now being seen in some non-native areas across the United States. They are schooling fish by nature and become semi-aggressive as they age. They are happiest in a tank with a rocky substrate and low lighting. They prefer tanks that mimic their natural habitat. The blind cave tetra does not let its lack of sight keep it from getting food. Researchers have debated if the blind tetra and the surface-dwelling tetra are two different species, but have settled on them being the same. Mexican Tetra ( Astyanax mexicanus) Mexican Tetra Evolution Research shows this is a combination of cellular degeneration in the lens of the eye and natural selection.
This is an adaptation that has evolved over many generations of these fish living in completely dark environments. The Mexican Tetra that gets access to sunlight has eyes, while the fish that does not see the sun is born without them. One lives in waters that get access to sunlight and the other lives in dark caves. There are two types of Mexican Tetra fish. The Mexican Tetra is blind as an adaptation to where they live. Mexican Tetras are valued for their peaceful nature and intriguing look. They come from a subtropical climate and prefer warmer waters. They spend most of their time in midlevel water above rocky, sandy riverbeds. Mexican Tetras are native to Texas and Mexico living in the Lower Rio Grande and the Nueces and Pecos Rivers. In the blind form, they have no eyes and no pigment which makes them pinkish-white in color. Both forms have triangle-shaped dorsal fins, pointed pectoral and anal fins, and a forked caudal fin. Mexican Tetras have a typical teardrop body shape found in most characins. Mexican Tetras are the only characid species native to the United States. The blind variant is a popular fish among freshwater aquarists. These fish come in two forms: with eyes and without eyes. The Mexican Tetra, Astyanax mexicanus, is a freshwater fish also known as the Mexican Blind Cavefish or Blind Cave Tetra.
0 kommentar(er)
