Which fish type is described as being less susceptible to piscicides?

The correct choice identifies catfish as being less susceptible to piscicides, which are chemical agents used to control fish populations. This can be attributed to several biological and physiological characteristics of catfish.

Catfish have a unique respiratory system that allows them to extract oxygen from both water and air, giving them a survival advantage in environments where other fish might be more vulnerable to chemical exposure. Furthermore, catfish's hardiness and adaptability to varying environmental conditions make them more resilient to toxicants compared to other fish species like trout, perch, and goldfish.

Trout and perch are more sensitive to various chemicals due to their metabolic processes and preferred habitats, which often do not provide the same protection as the environments preferred by catfish. Goldfish, while somewhat hardy, still do not exhibit the same level of resistance as catfish when exposed to piscicides. These factors combined illustrate why catfish are notably less susceptible to the effects of these chemicals.