Animal Biology: X-ray Tetra

Animal Biology: X-ray Tetra

Introduction

The purpose of this study is to expand the boundaries of our knowledge by exploring some relevant facts related to the biology of X-ray Tetra or Pristella maxillaris. There are more than 21,000 species of fish. Fish can be separated into three classes: Agnathans, Chondrichthyes, and Osteichthyes. Agnathans lack biting jaws and paired fins. They include lampreys and hagfish.Osteichthyes, or the bony fish, possess skeletons made up of true bone and include nearly all other living fish.Fish can be distinguished by the manner in which they maintain the water balance in their bodies. The body fluids of saltwater fish such as pollock (Pollachius virens) have less salt than the surrounding water. These fish are always losing freshwater through osmosis. They drink seawater and excrete excess salt through their gills and urine. The body fluids of freshwater fish such as brook trout (Salvelinus fontinalis) have a higher concentration of salt than the surrounding water. They urinate large quantities of freshwater and use their gills to absorb salt. Fish control the intake of and expulsion of fluids by osmoregulation. Many fish have swim bladders to control their buoyancy.

These are gas-filled organs that contain more or less gas as the fish needs more or less buoyancy. Some species of fish have swim bladders connected with their blood streams so that gases can pass back and forth between the bloodstream and the bladder. Most larvae and juvenile fishes have swim bladders, but may lose them after they reach adulthood. For example, bottom fishes (demersal) have no need for swim bladders. Sharks also lack swim bladders and must stay in constant motion to avoid sinking.

Fishes have streamlined shapes to permit high-speed travel in the water. This is especially true of high-level predators such as tuna. Aquatic animals of the superclass Pisces, which breathe by means of gills. The jawless fish, the Agnatha or Ostracoderms, are sometimes put into a phylum of their own. Fossil agnathans are the evidence of the earliest vertebrates; they were well established in the Ordovician period (500 million years ago). Agnathans had, in addition to bony skeletons, formidable bony armor plates.In the next section, the author will examine different biological aspects of X-ray Tetra or Pristella maxillaris

Discussion & Analysis

Pristella maxillaris

Pristella maxillaris is the only species in the genus Pristella and is commonly known as the golden pristella tetra or X-ray tetra because of its highly transparent body. It is a widely distributed and adaptable fish, being found in coastal rivers of Brazil, French Guiana, Guyana, and Venezuela in both acidic and alkaline waters. Unlike most other characins, it is tolerant of (and sometimes found in) slightly brackish water. It is small (around 5 cm) and lives in large groups, and males can be distinguished from females by being smaller and thinner than the females. Like most other tetras, it feeds primarily on small insects and planktonic animals.

X-ray Tetra breathe oxygen dissolved in water. Water flows sequentially through the mouth, gills, where gas exchange occurs ...