There are many varieties of carnivorous plants and the needs may be different from one to another. Carnivorous plants grow in very humid environments, generally in natural peat bogs.
Most of the time, it is useless and harmful to provide them with fertilizer to feed them. They fend for themselves, capturing their prey and extracting the few minerals found in their substrate. The frequency of watering depends on their specific needs and the method of cultivation (reconstituted peat bog, pot, terrarium, indoor, outdoor)