214 THE TROUT 



or two fish are not lurking behind ready to devour 

 any smaller fish put in. At the end of the season it 

 is well before re-stocking to clear out all mud and 

 sediment and to allow the ponds to remain empty 

 for some time, the longer the better. The exposure 

 to the air and sun has a very wholesome effect. 



It is an excellent plan to introduce into your 

 ponds suitable water- vegetation by planting it at 

 intervals on the bottom. ' Water-plants/ says Stone, 

 * consume carbon and return oxygen. Trout consume 

 oxygen and return carbon. By putting plants and 

 fish together, therefore, we avail ourselves of one of 

 Nature's great universal agencies, in balancing vital 

 forces against each other, and maintaining the equi- 

 librium on which the continuance of organic life 

 depends. 7 



There are, however, many unsuitable kinds of 

 water-plants. What you want is vegetation which 

 will afford plenty of shade, and which will form a 

 suitable ' cover ' and pasture for insects, snails, &c. 

 ' 111 weeds grow apace ; ' and it must not be a plant 

 which will give trouble by developing a rank growth 

 and choking the pond. 



I know of nothing better adapted to the purpose 

 than the water star-wort (Callitriche verna). Three or 

 four clumps of it flourish in each of the rearing-ponds 



