In addition to fish feed development, innovation in catfish feeding technology is also an important issue. While catfish farming has been around for years and much is known about nutrition and feeding, catfish feeding is still an art and a science. Commercial catfish farms do not use standard feeding methods, which vary by species and farm. The question that fish farmers need to think about every day is how much catfish should be fed each day so that the catfish can grow healthily without adversely affecting the water quality. However, it is often difficult for catfish to obtain enough food because various problems can result in the limited amount of feed provided to the fish. The methods of feeding catfish are different, and the interference factors are also different, so farmers need to formulate a suitable feeding system according to the conditions of the farm.
How to feed catfish scientifically is a difficult, highly subjective process because there are differences between catfish farmers. Although there is a lot of research and practice in this area, it still needs continuous improvement in different situations. Changes in rearing practices are influenced by a variety of factors, such as farming system, fish size, ability to manage water quality, rearing experience, and financial support. In general, fish should be fed once a day. However, depending on water quality variables and the health of the fish, it is recommended to limit the daily feed amount or reduce the frequency of feeding. Long-term feed allowance should not exceed 100-125 pounds per acre per day. Most catfish users feed once a day, 7 days a week during the warmer months. While feeding twice a day may slightly improve fingerling growth, the cost of multiple feedings on large catfish farms makes it impractical. For large farms, fish farmers often use mechanical feeders to blow the feed onto the water. The feed should be spread over as wide an area as possible to give as many fish as possible an equal opportunity to eat. Feeding with prevailing winds keeps the feed afloat in the pond and minimizes the amount of feed that washes ashore. Overfeeding should be avoided as wasted feed increases production costs.
Feeding rate and frequency depend in part on the size of the fish. Small juveniles and fry need to be fed diets that are often too high in protein, often in excess. Small fish have high energy demands and must feed almost continuously, every hour. Overfeeding small fish is not as severe as overfeeding larger fish, which require only a small amount of feed. Feeding rate, frequency, and feed protein content should be reduced as the fish grow.
Feeding the fish is time-consuming and expensive. The availability of workers, the size of the farm, the production system, and the type and size of fish raised all affect how often they are fed. Due to labor and time constraints, large catfish farms with numerous ponds are often fed only once a day, while smaller farms may be fed twice a day. In general, growth and feed increase conversion with increasing feeding frequency. In indoor intensive fish farming systems, fish may be fed up to five times a day to maximize growth at optimal temperatures. Many factors can affect the feeding rate of fish. These include life stage, time of day, season, water temperature, dissolved oxygen levels and other water quality variables. For example, feeding pond fish early in the morning is not recommended because the water has low oxygen levels and is not conducive to feeding.
In contrast, in an oxygen-based recirculating aquaculture system, fish can be fed at almost any continuous supply time. During winter and cooler water temperatures, the feeding rate of warm water fish in ponds decreases and should decrease proportionally. The acceptability, palatability and digestibility of feeds vary depending on the raw material and feed quality. Fish farmers closely monitor feeding activities to help determine feed acceptance, calculate feed conversion and feed efficiency, monitor feed costs and track feed requirements throughout the year. Farmers can calculate optimal feeding rates based on the number of fish in the pond. Farmed fish are typically fed 1-5% of their body weight per day.
In catfish farming, rearing is a highly diverse process. Some fish farmers use computer programs to determine feeding rates as a percentage of fish body weight. This method of feeding a prescribed amount of feed based on the biomass of the fish in a particular pond works best when the biomass in each pond is known and a reasonably accurate estimate of the feed conversion ratio can be made. However, determining biomass after multiple harvests and restocking is a challenge, as most catfish producers only remove fish large enough to sell and replace harvested fish with fingerlings. In fact, many catfish farmers’ inventory estimates are based on feed intake. Therefore, catfish are usually fed once a day until they reach what is called a satiety state (that is, within about 20 to 30 minutes after feeding the fish). Producers must choose how much and how often to feed catfish each day, as feeding activity varies with fish size and age, water temperature, water quality, and fish health. No two fish ponds are exactly the same, and each fish pond and daily eating habits will vary greatly. Fishermen and farmers should feed high-quality fish feed every day, which will not pollute the water quality.
However, depending on water temperature, water quality and fish health, sometimes it may be better to limit the daily feed amount or reduce the frequency of feeding. Most commercial ponds are relatively large (usually 10 acres or larger), and it is important to spread the feed over a large area to allow as many fish as possible to access the feed. It is best to feed on all sides of the pond if wind conditions permit. If there is wind, the feed must be distributed along the upwind side of the pond to prevent it from being washed ashore.