Which fish are considered more susceptible to chlorine toxicity?

Small freshwater fish are considered more susceptible to chlorine toxicity for several reasons. Firstly, smaller fish have a greater surface area-to-volume ratio compared to larger fish, which can facilitate the absorption of harmful substances, including chlorine, through their gills and skin. This increased exposure can lead to more pronounced physiological impacts from chlorine toxicity.

Additionally, small freshwater fish typically have higher metabolic rates, making them more vulnerable to environmental stressors such as chlorine. Their physiological systems are more actively engaged in processes like respiration and osmoregulation, which can be disrupted by chlorine exposure, leading to toxicity symptoms.

In contrast, saltwater fish often have adaptations that allow them to cope with higher levels of fluctuating environmental changes, including salinity and potential toxins, which can make them relatively more resilient to chlorine. Large freshwater fish generally have a larger mass and volume, which may allow for greater dilution of chlorine in their bodies compared to smaller fish.

While all fish can be affected by chlorine toxicity, the susceptibility is particularly acute in small freshwater species due to their unique physiological characteristics and environmental lifestyle, emphasizing the need for careful management of chlorine levels in their habitats.