SALMON AND TROUT CULTURE. 457 



hatching troughs, as the little fences which are effectual to keep 

 the young fish in the troughs will also prevent the empty shells 

 from floating away \ but this is the work of a few minutes only 

 every day. Either the whole tray full of hatching fish may be 

 turned out into a pan, and the empty shells poured off, or the 

 greater part of the shells can be skimmed off with a cup or 

 small muslin net ; whichever plan is adopted, it should be 

 repeated until all the fish are hatched, and the troughs are 

 perfectly clean. A few fish may have to be assisted out of 

 their shells by the use of a camel's hair pencil, as they some- 

 times hatch out tail instead of head first, and the struggles 

 of the young fish to get free sometimes end in their being 

 strangled. 



A small percentage of the fish always die in hatching, and 

 must be speedily removed. Deformities and monstrosities are 

 occasionally met with : some have two heads and one body 

 (Salmonese Twins !) ; others have one head and a body and 

 a half ; a few also are hatched with three heads ; a few with 

 four eyes, and some with no eyes at all. These are placed in 

 a spare corner for observation, or preserved in spirits they 

 never live more than five or six weeks. 



There will soon be left a wriggling mass of veritable young 

 trout, huddling together into every corner of the trough out of 

 the light. There is no danger in this, unless the troughs are 

 over-crowded with fish. In this case comes 'gill fever,' or 

 inflammation of the gills, a plague with which I am happy to 

 say I have never been troubled. The effect of inflammation 

 of the gills is to eat away a portion of the gill coverings, 

 and if the fish survive, there is always trace of it to be seen 

 in after-life, nor do they ever thrive or have so good an 

 appearance. 



A pisciculturist having anything like a demand for his 

 ova will, ere this, be able to thin out his stock considerably by 

 finding unoccupied troughs ; at this time also the perforated tray 

 system seems to offer the greatest advantages, as the fish can 

 be prevented from over-crowding by being kept in separate 



