求翻译：鱼类是最古老的脊椎动物。它们几乎栖居于地球上所有的水生环境━━从淡水的湖泊、河流到咸水的大海和大洋。鱼类是终年生活在水中，用鳃呼吸，用鳍辅助身体平衡与运动的变温脊椎动物。已探明的约20000余种，是脊椎动物亚门中最原始最低级的一群。鱼肉富含动物蛋白质和磷质等，营养丰富，滋味鲜美，易被人体消化吸收，对人类体力和智力的发展具有重大作用。鱼体的其他部分可制成鱼肝油、鱼胶、鱼粉等。 有些鱼类如金鱼、热带鱼等体态多姿、色彩艳丽，具有较高的观赏价值是什么意思？

The fish is the most ancient vertebrates. They inhabit almost all aquatic environments on Earth ━ ━ sea to the salt water from freshwater lakes, rivers and oceans. Fish throughout the year live in water and breathe using gills, fins auxiliary body balance and movement variable temperature vertebrate

Fish is one of the oldest vertebrates. They are almost all animals on Earth living in the aquatic environment -- from fresh water to the lakes, rivers and the ocean salt water of the ocean. Fish are living year round in the water, breathing with gills, fins with secondary physical balance and moveme