1.The concentrations of food organisms should not be less than 1000-1500 food items per liter.F.G.Martyshev Pond Fisheries.1983

2.

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Rotifers are fed at a rate of three to five rotifers per ml until larval fish can consume larger foods at about day 11 post-hatch. Larval mullet ( Mugil cephalus ) require a food density of 10 rotifers per ml, when there are 25 to 50 larvae per liter, through day 40. Once rotifers are harvested from the culture system food is often limited, so the nutritional value of rotifers decreases over time. It is best to feed them to fish at least twice a day, or replenish them whenever rotifer density drops below a des- ignated number per ml. For exam- ple, in red drum larval culture, replenishment should occur when rotifer density drops below 3 per ml. Since one fish larva can eat as many as 1,900 rotifers per day, from 13,300 to 57,000 rotifers are needed to feed one fish larva through this period (depending upon fish species and rotifer size). Most producers estimate three times the amount of rotifers actually eaten (1,900 X 3 = 5,700 rotifers per day) are fed per larva. Therefore, as many as 39,900 rotifers (for a 7-day period) to 171,000 rotifers (for a 30-day peri- od) may be required to feed one fish larva. Feeding too few rotifers often results in slow growth and too much size variation; feeding too many rotifers can cause the fish to ingest so much that assimi- lation becomes a problem. For most marine finfish species being reared indoors, the weaning of larvae from live rotifers and Artemia to dry food should begin well in advance of the transfor- mation from larvae to juveniles. This transition might be timed to take 3 days or as long as 2 weeks, but should be done gradually. Food particles should be the largest that can be swallowed easily by the fish (one-fourth to one- half of mouth width). Starter feeds should contain 50 to 60 percent high quality protein. As an exam- ple, in the past red drum larvae were generally fed rotifers from day 3 post-hatch to day 11, Artemia nauplii from day 11 to 21, and then weaned onto dry feeds. More recent protocols include the co-feeding of micro-particulate larval diets starting at day 5. Although live zooplankton is still used, dependence on them as the sole nutrient source has been significantly reduced, and the need to wean the animals from live foods is eliminated.

Artemia nauplii are maintained in the larval culture tank at densities of 0.5 to 2 per ml for most species of finfish and up to 6 per ml in the more advanced larval shrimp stages. To estimate the amount of Artemia required one must consider both the volume of the tank and the expected number of Artemia the larvae will consume. Based on the stage or the age of the larvae, estimate a daily Artemia requirement per ml. This feeding rate can be adjusted slightly, depending on the stocking density (number of target larvae per litre) and the rate at which the Artemia are consumed. The total requirement is then calculated by multiplying the predicted requirement per ml by the total volume of the rearing tanks. Each gram of cysts contains approximately 200,000 to 300,000 cysts. Artemia generally have at least a 50 percent hatch.

You can refer to the following article to get the answer.

You can refer to the following article to get the answer.