In the first 75 years of production at Mt. Parnell Fisheries, fish were grown and harvested the "old fashioned way", in outdoor ponds. Utilizing a 40-tank Recirculating Aquaculture System has allowed diversification of the stock available to customers while continuing to supply quality pond fish that the company's foundations were built upon. Fish raised in outdoor earthen ponds exist in an ecosystem where many things are unpredictable and uncontrollable. One of the many challenges of growing fish indoors is to eliminate as many stressors as possible while substituting for the positive attributes that the fish enjoy in a balanced pond environment, such as natural food and lots of space.
In 1998, Mt. Parnell broke ground for a 6300 square foot building in order to establish a new method for raising goldfish indoors in a recirculating system. Mt. Parnell's new system was designed as a result of many years of research and the operation of a small-scale pilot system. The building currently contains forty, 400 gallon production tanks separated into two independently operating recirculating systems.
The fish get their start in the outdoor ponds, but are brought to the indoor tanks while still very tiny. Each tank is stocked with several thousand small, sub-saleable sized fish. Once the fish have had a few days to get used to their new environment, they are introduced to a specialized feed, dispensed every hour via automatic feeders. The recirculating system building is temperature controlled to keep the water temperature constant. This helps to optimize the growth potential of the fish in contrast to the fluctuating water temperatures in the outdoor ponds.
Four filtration devices work to keep the water "clean." These devices filter the water chemically, mechanically, biologically and through gas transfer. The water from each production tank passes through these filters several times per hour. Proper filtration helps ensure that no metabolic wastes or their by-products have a chance to build up in the tanks containing fish. Clean water is what allows the fish to thrive in their artificial indoor environment.
Fish are harvested from the system at various sizes based on customer demand. When the fish are ready to be sold, well water is introduced to the individual tank since the recirculating system water temperature is considerably higher than the water used in the holding facilities. Once the tank water is cooled to match the temperature of the well water, the fish are moved to a holding pool and prepared for shipment. The process can now start over with an empty tank available for more small fish.