These fish can, generally, be raised to a harvestable size in less than 2 years and even as little as 6 months, depending upon the species, food quality and growing conditions.
Catfish
Several different species of catfish are popular choices for growing in freshwater ponds. In the United States, these include the channel, blue, billhead and flathead catfish. These species are tough and resilient, growing quickly when fed well. It takes around 15 to 18 months for catfish to reach a harvestable weight of between 1 and 1 1/2 lbs. Catfish are particularly good at handling ponds with low oxygen levels and poor environmental conditions. Predominantly predatory fish, catfish do best on higher protein diets.
Tilapia
Indigenous to Africa and the Middle East, tilapia are hardy fish that grow quickly, even when pond management is minimal. Tilapia are so prolific that they are sometimes referred to as "aquatic chickens." As true omnivores, they will eat just about anything, making them very easy to raise. These fish are usually harvested when 1/2 to 1 lb. in weight. With good water and weather conditions, proper care and good nutrition, this can be accomplished in as little as 6 months.
Carp
Carp can also be raised for food in ponds. Species include the common carp, silver carp and bighead carp. All carp are introduced species. Some carp species can grow to well over 60 lbs., although most are harvested at between 5 and 10 lbs. Carp grow quickly and can put on that much weight in as little as 2 years. While carp are excellent for eating, they do tend to be somewhat bony.