The blood of fish has a continuous age distribution of erythrocytes. The properties of young and old erythrocytes differ with young erythrocytes being functionally much more versatile than old erythrocytes, which have higher haemoglobin content. Factors which affect the formation and breakdown of erythrocytes are reviewed. Erythropoiesis in fish is largely similar to that in mammals. However, definitive erythrocytes are mainly formed in the anterior part of the kidney, and erythropoietin is secreted mainly from the heart. Senescence of erythrocytes in fish has not been studied in detail, and consecutively the factors causing aging of erythrocytes in man are discussed. A major factor causing aging of erythrocytes is oxidative stress, which is also a major effect of toxicants on fish erythrocytes. Consequently, apparent age distribution of circulating erythrocytes will be affected by environmental pollution. At present, it is completely unknown, if the changes in age distribution of erythrocytes play a role in pollutant responses or if the age distribution of erythrocytes is actively regulated during environmental adaptation.

鱼的血液具有持续的年龄分布的红细胞。年轻人和老年人的红细胞的特性不同，年轻人的红细胞在功能上比血红蛋白含量更高的年轻人的红细胞更为广泛。综述了影响红细胞形成和分解的因素。鱼类中的红细胞生成与哺乳动物中的相似。然而，确定性的红细胞主要形成在肾脏的前部，而促红细胞生成素主要从心脏分泌。鱼类中红细胞的衰老尚未进行详细的研究，并且随后讨论了导致人中红细胞衰老的因素。引起红细胞衰老的主要因素是氧化应激，这也是有毒物质对鱼类红细胞的主要影响。所以，循环红细胞的明显年龄分布将受到环境污染的影响。目前，完全不知道红细胞的年龄分布变化是否在污染物响应中起作用，或者在环境适应过程中是否主动调节了红细胞的年龄分布。