What is a NPT?
An NPT is a natural planted tank, basically it us a tank with a soil substrate where the plants and fish balance each others needs. The fish will still need to be fed though. Plants get most of their co2 from decomposing organic matter in the soil and from fish food. A mature aquarium can go for 6 months without a water change. These aquariums are great for raising fry in as they are full of microorganisms for them to feed on. This method is the brain child of Miss Diana Walstad, she wrote an entire book on the consept. You will not need to use filtration in these tanks other than a power head as they compete with the plants for ammonia which plants prefer over nitrate. This is a great method for those who do not want to pay the hundreds of dollars for a "high tech" tank with heavy fertilisers,co2 and strong lights.