Like humans and other animals,
fish suffer from
diseases and
parasites. Fish defences against disease are specific and non-specific. Non-specific defences include skin and scales, as well as the mucus layer secreted by the
epidermis that traps
microorganisms and inhibits their growth. If
pathogens breach these defences, fish can develop
inflammatory responses that increase the flow of blood to infected areas and deliver
white blood cells that attempt to destroy the pathogens.