Groom long-haired guinea pigs with a wide-toothed comb. Hold the hair above where you’re brushing it in order to stop yourself pulling on the root and hurting the animal. Thinner combs can be used for the shorter hair in the belly and leg regions.
Some owners actually trim long-haired GPs' fur right back, so that the haircuts only need to be carried out two or three times a year.
Guinea Pigs with long hair need more grooming
As with short-haired varieties, long-haired guinea pigs may need the area around their grease-gland cleaned regularly. See Guinea Pig Grooming for more details.