20 



THE 



AQUARIUM 



^ 



like the different Danios, will hunt for 

 the eggs and eat them as soon as the 

 spawning is finished, if not prevented 

 from doing so by either the eggs or the 

 fishes being removed to another tank, 

 or by having the bottom of the tank 

 closely covered by plants, as Elodea and 

 Myriophyllum, kept down with small, 

 smooth — not sharp-edged — stones. 

 But the safest way to protect the eggs 

 and the young will be to remove the 

 parent fishes to another tank. 



The young, after they are hatched, 

 keep between the plants until their yolk 

 sac is absorbed; after this they will hunt 

 for Infusoria, of which the tank ab- 

 solutely must have plenty, if success is 

 anticipated in raising the young. As 

 long as the Infusoria are needed for 

 food, no Daphnia should be dropped 

 into the tank, because the Daphnia 

 devour the Infusoria. Infusoria may be 

 grown with perfectly dried water plants, 

 especially Lemna, or Lettuce, powdered 

 and strewn on the surface of the water 

 in the tank, or by placing some hay in 

 a glass with water and letting it stand in 

 the sun for a few days until the water 

 gets yellow; or by using Infusoria 

 producing artificial fish food, for in- 

 stance Thum's, which can be bought in 

 New York City, 



When the young are from ten to fif- 

 teen days old, they will take small 

 Daphnia and Cyclops, later finely scraped 

 beef. At the age of six weeks, with care- 

 ful treatment they will have reached a 

 length of about an inch, and already 

 have the bright red color on their fins 

 and tail. Different kinds of Tetra- 

 gonopterus are imported, but rubropictus 

 is the foremost in shape and color. It 

 may be bought quite reasonably; breed- 

 ers and importers in Germany charge 

 two dollars a pair for prime specimens. 



History of Fish Culture. 



W. E. MEEUAN, Director Philiuh-lpliia Public 

 Aciuiirium. 



IT is now generally accepted as a fact 

 that fish-life in fresh water streams 

 and other fresh water bodies can no 

 longer be maintained, excepting in very 

 remote places, by the fish themselves 

 by natural propagation. The steady 

 increase in population, and the resultant 

 increased demand for fish for food has 

 produced a greater drain on the supply 

 of fish life than the mature fish them- 

 selves can overcome. Hence in order 

 that the demand for fish be met, it 

 became necessary for man to assist 

 nature, by what is called artificial pro- 

 pagation. If it were not for what he is 

 accomplishing in this direction, it is 

 safe to say that many of our familiar 

 and best food and game fishes would by 

 this time be exterminated. 



The fish culturist employs three 

 methods of propagating fish, one is by 

 means of troughs with water running 

 under and over wire netting trays, a 

 second is by keeping fish eggs revolving 

 in glass jars filled with water, and the 

 third is by means of ponds, in which 

 fish are allowed to spawn naturally and 

 hatch their eggs, guarding both mature 

 and young fish from their many 

 enemies. Only very heavy eggs like 

 those of the trout and salmon are 

 hatched by means of the troughs and 

 trays. Semi-bouyant eggs and those which 

 are yielded in vast quantities are hatched 

 by the jar method, while pond culture 

 is reserved for those fish, from which 

 eggs either cannot be taken at all or 

 which cannot be taken excepting with 

 much trouble or possible injury to the 

 fish culturist, and a few nest building 

 fishes that take vigilant care of both 

 eggs and young, and where fertilization 



