what signs we should look at to decide when the dry food should be offered to fish after feeding them live food and if there any method to make them eat the food?
Many thanks
This depends on the species and can range for a few days to as long as several weeks. Generally, the digestive anatomy and digestive enzyme profile of the larva have to be ready first before successful weaning can occur. Which species are you working on?
Depending on species, there are techniques like manipulating the size, shape or density of the feed, use of attractants/certain colors; or physico-chemical approaches like manipulating light, color of the tank, turbulence of the water, temperature, etc.
During Fish larval rearing , fry will undergo different stages and finally metamorphosed into fingerling. In nature fish larvae being pelagic feed on zoo plankton, which are moving in the entire water column. During larval stages fish larvae digestive system is adopted to live feed which is consisting 70% water content. In general fingerlings, after metamorphosing, being weaned on pellet diets (< 10 % humidity) gradually replacing live feeds for a period of 15-20 days to make fingerlings digestive system adoptable to pellet diets. Basically live feed is used in early stages of larval rearing for two reasons, 1. it provides exogenous enzymes that are required for fish larvae and the 2. live feed is pelagic in nature available all the time to fish larvae to feed. Of late micro encapsulated diets are being used during early stages of larval rearing by incorporating required exogenous enzymes in diets and making floating diets.
To answer this question requires feeding trials with weaning groups of larvae on dry diet different times after the onset of feeding. This is the general scheme. However, as already mentioned by E. Floreto, the time of weaning depends on the species, the diet as well as rearing conditions. For most aquaculture species the time period after onset of feeding, in which live diet is necessary for larval rearing, is reduced more and more with increasing knowledge on diet requirements, rearing conditions, optimal water temperature, etc.
thank you all for your answers. our fish are weaning normal now. Apparently they like higher density
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