FEEDING OF CARP SPAWN

Nursery rearing of fish seed generally has two distinct phases: (i) rearing of post-larvae to fry and (ii) rearing of fry to fingerling. In the earlier developmental stage the fry are dependent on natural live food from the pond itself, which can be enhanced through pond fertilization (mustard oil cake) and manuring (caw dung). As the post-larvae develop, their diet changes from microorganisms such as protozoa, to larger prey items such as rotifers.

At the post-larvae stage, due to their feeding habit and mouth size, the fish will not take any artificial feed even if it is supplied. Nursery operators in Bangladesh do not normally use wild-caught food. Instead, they produce live food in the nursery ponds and, as the fry grow bigger, they start supplying supplementary feed. A typical feeding schedule for carp post larvae/fry is given in Table 4.
Once the fry are released into the nursery ponds, both hatchery-produced seed and wild seed receive the same treatment described above. Within 3–5 days the natural food produced in the nursery pond is usually consumed and supplementary feeding is needed. The feed is usually prepared at the farm, with attention being given to maintaining a good nutritional balance, and sometimes the food is fortified with vitamins and minerals. Wheat or molasses are sometimes used as binders. Seed growers use only mustard oil cake mixed in water and the solution is sprayed over the water.

Subsequently rice bran is mixed with mustard oil cake at a ratio of 1:1. At the fingerling stage, oil cake, rice bran or wheat bran is used, along with other protein sources like fishmeal

Table 4
Feeding schedule of carp post larvae/fry for the first 50 days after stocking

or blood from cattle. At this stage the feed is normally granular or in pellets. In carp nurseries the feed is normally applied at around 10 a.m. If feed is applied twice a day, the second feeding is in mid-afternoon, with equal amounts given at each feeding. Some carp nursery farmers use artificial feeds for catfish and shrimp in order to achieve faster growth.