The great ecological tolerance of aphaniid tooth-carps (Aphaniidae) suggests that the genetic-based adaptation to divergent osmoregulatory environments may be an important driver of the aphaniid fish diversity. This study was conducted to assess gill mRNA expression levels of two osmoregulatory genes, i.e., the CLC-3 and the Na⁺/K⁺-ATPase in two tooth-carps inhabiting the freshwater (FW) spring and salty water (SW) river. The expression pattern of genes was examined by quantitative real-time PCR. The number of ionocytes in the gill tissues was counted and compared using histological sections. The expression of CLC-3 in the FW fishes was 3.4 fold higher than that in the SW specimens, which highlighted the role of CLC-3 as a hyposmotically activated chloride channel. The expression of Na⁺/K⁺-ATPase was increased by 5.6 fold in the SW fishes. This upregulation in the SW fishes leads to the excretion of excess ions and maintains the homeostasis. The histological sections demonstrated that the ionocytes were distributed in the interlamellar region of the gill filament and that the average number of ionocytes was more in the SW fishes. This is probably an ecophysiological response to the saline condition of the habitat. The results of this study revealed that the examined osmogenes likely play an essential role in the adaptive responses of the studied killifishes to the variable osmotic conditions.

a鱼鲤鱼（Aphaniidae）对生态环境的耐受力强，表明基于遗传的适应性渗透调节环境的适应可能是a鱼鱼类多样性的重要驱动力。进行了这项研究以评估两个渗透调节基因，即CLC-3和Na ⁺ / K ^+的ill基因mRNA表达水平。-居住在淡水（FW）泉水和咸水（SW）河中的两只tooth鱼中的-ATPase。通过定量实时PCR检查基因的表达模式。使用组织切片对using组织中离子细胞的数量进行计数和比较。FW鱼中CLC-3的表达比SW样品高3.4倍，这突出了CLC-3作为低渗激活的氯离子通道的作用。Na ⁺ / K ⁺的表达在西南鱼类中，ATP酶增加了5.6倍。西南鱼类的这种上调导致多余离子的排泄并维持体内平衡。组织学切片显示，离子细胞分布在the丝的层间区域，而西南鱼类中离子细胞的平均数量更多。这可能是对栖息地盐碱状况的生态生理反应。这项研究的结果表明，被检查的渗透基因可能在被研究的鱼类对可变的渗透条件的适应性反应中起着至关重要的作用。