The present invention provides an aquaculture system for rearing aquatic creatures. The aquaculture system includes a rearing tank adapted to contain water for rearing the aquatic creatures, wherein the aquatic creatures produces waste which produces ammonia, a first denitrification apparatus adapted to convert the ammonia to nitrate, such that the first denitrification apparatus includes a least one culture media adapted to culture denitrifying bacteria and is adapted to channel a first water flow from the rearing tank through the first denitrification apparatus and back to the rearing tank, and a second denitrification apparatus adapted to convert the nitrate to nitrogen gas, such that the second denitrification apparatus includes at least one culture media adapted to culture denitrifying bacteria and is adapted to channel a second water flow from the rearing tank through the second denitrification apparatus and back to the rearing tank, such that the first water flow is faster than the second water flow. The present invention further provides a method of rearing aquatic creatures using the aquaculture system.