68 WHOLESALE BREEDING 



Goldfishes are hatched in the greenhouse from February until 

 May. The young, as stated in the previous chapter, should not be 

 placed out until the weather is settled, but there is a magic about out- 

 doors which puts growth and vitality into the fish which the cunning- 

 est devices of temperature, plants, food, aeration, etc., cannot success- 

 fully imitate in the greenhouse. There has been much speculation as 

 to why fishes do not do as well as might be expected in greenhouses. 

 The author suggests that the water is too dead, owing to lack of 

 evaporation, the atmosphere being already charged with dampness. 

 Evaporation produces cold. The cold, oxygenated water drops to the 

 bottom, thereby setting up a beneficial circulation of re-vitalized water. 

 Also there is more microscopic life falls on the water outside than 

 indoors. A partial renewal of water in indoor tanks is undoubtedly 

 beneficial and is one means of at least partially securing that fresh- 

 ness of water which we have outdoors. Those handling fishes in 

 wholesale quantities in greenhouse or other large indoor pools usually 

 maintain a small spray of running water. This should in no sense 

 be of sufficient quantity to be regarded as running water, but merely 

 enough to add a trifle of freshness and oxj'gen. Stock accustomed to 

 actual running water is liable to suffocate when placed in an ordinary 

 aquarium. Retail dealers are not always conscientious in this mat- 

 ter. In order to carry a large stock in a small space they have to 

 resort to a liberal use of running water. They dip fishes directly out 

 of such tanks to sell for use in household aquaria, knowing full well 

 that the chances of survival are poor. It is by no means impossible, 

 or even difficult, to accustom such stock to still water, but the change 

 should be brought about slowly. Frequent partial changes of water 

 at first, gradually increasing the length of time between them, will 

 accomplish the result. 



Some years ago Mr. Wm. P. Seal devised a fish-breeding house 

 of a somewhat difi:erent character from the ordinary greenhouse, and 

 the idea has been generally accepted as correct in principle. The 

 structure is long and narrow, with solid roof. The lighting is from 

 window sashes in the sides, these being swung or pivoted so as to 

 admit the air in summer. The objections to the ordinary type of 

 greenhouses are, first, too much light for fishes and plants, producing 

 an excessive growth of algae (including green water) ; second, high 

 cost of heating in cold weather and too much heat in the warm season ; 

 third, attendant risks due to glass breaking from various accidents, 

 including, in some sections, large summer hailstones. Where an all- 

 glass greenhouse is used, the light is cut down in summer by painting 



