Adult fleas are like small, wingless insects with dark-coloured bodies measuring between 1mm and 3mm in length. The body of the flea is flattened from side to side and is covered with pointed spines which allow it to move easily through the hairs or feathers of its host.

Flea larvae emerge from the eggs to feed on any available organic material such as dead insects, faeces and vegetable matter. They are blind and avoid sunlight, keeping to dark places like sand, cracks and crevices, and bedding. Once the flea reaches adulthood its primary goal is to find blood. Adult fleas only have around a week to find food once they emerge, though they can survive two months to a year between meals.