The ability of fishes to adapt to any aquatic environment seems limitless. It is enthralling how new species keep appearing at the deep sea or in subterranean environments. There are close to 230 known species of cavefishes, still today the best‐known cavefish is Astyanax mexicanus, a Characid that has become a model organism, and has been studied and scrutinized since 1936. There are two morphotypes for A. mexicanus, a surface fish and a cavefish. The surface fish lives in central and northeastern Mexico and south of the United States, while the cavefish is endemic to the “Sierra del Abra‐Tanchipa region” in northeast Mexico. The extensive genetic and genomic analysis depicts a complex origin for Astyanax cavefish, with multiple cave invasions and persistent gene flow among cave populations. The surface founder population prevails in the same region where the caves are. In this review, we focus on both morphotype's main morphological and physiological differences, but mainly in recent discoveries about behavioral and metabolic adaptations for subterranean life. These traits may not be as obvious as the troglomorphic characteristics, but are key to understand how Astyanax cavefish thrives in this environment of perpetual darkness.

中文翻译：

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地下生活：Astyanax穴居鱼的行为，新陈代谢和其他一些适应。

鱼类适应任何水生环境的能力似乎是无限的。令人着迷的是，新物种如何在深海或地下环境中不断出现。有近230个知cavefishes的品种，今天仍然最有名的cavefish是Astyanax mexicanus，一个Characid已经成为一种模式生物，并进行了研究和审查自1936年以来有两种形态为A. mexicanus，表面鱼和一个洞穴鱼。表层鱼类生活在墨西哥中部和东北部以及美国南部，而洞穴鱼是墨西哥东北部的“ Sierra del Abra-Tanchipa地区”特有的。广泛的遗传和基因组分析描述了Astyanax的复杂起源洞穴鱼类，在洞穴种群之间有多个洞穴入侵和持久的基因流动。地表创始人人口主要分布在洞穴所在的区域。在这篇综述中，我们集中于形态学的主要形态学和生理学差异，但主要集中在关于地下生活的行为和代谢适应的最新发现中。这些特征可能不像原形特征那么明显，但对于理解Astyanax穴居鱼如何在这种永久黑暗的环境中壮成长至关重要。