The Rainbow Trout - Runkebjerg.dk

After the fry hatch they require but little attention until the umbilical sac is absorbed and thetime for feeding arrives. They are examined each day, and the dead fish and decayed matterremoved from the troughs, which are kept perfectly clean, and if possible provided with a thinlayer of coarse white sand on the bottom, to keep the fish in healthy condition. As the fish growthey should be thinned out in the troughs, from time to time, as their size may require. Whenthey first begin to feed, 12,000 to 15,000 fish to the trough are not too many; but by the time theyget to be 1 1/4 to 1 1/2 inches long they must be divided into lots of 8,000 to 10,000 to eachtrough; while with fish averaging 3 inches in length, 3,000 to 4,000 are as many as one troughwill accommodate. It is advisable to give as much room as is practicable.REARING-PONDS.Ponds for rearing trout are from 8 to 12 feet wide, and of any desired length up to 60 feet,which, for convenience in drawing them off and in feeding the fish, is about the extreme limit.The size, shape, and arrangement of the ponds must depend upon the ground on which they areto be constructed. If practicable, it is best to build them on a hillside, one above the other, withearth and piling embankments on the lower sides and at the ends.