236 FISH CULTURE 



the successful maintenance of an aquarium. 

 Some are of little value except as ornaments, 

 but others furnish oxygen in considerable 

 quantities, and so render it unnecessary to 

 change the water frequently. 



Goldfish are not the only species which may 

 be carried in an aquarium. Many other at- 

 tractive fishes may be kept in still water where 

 there is an abundance of oxygenating plants. 

 Indeed, within the last few years many tropical 

 fresh-water fishes have been introduced into 

 the United States for this purpose; some are 

 of remarkable beauty, and all afford constant 

 interest. Some of these foreign fishes bring 

 forth their young alive, others, after deposit- 

 ing eggs in the sandy bottom of the aquarium, 

 immediately dig a hole in another part, and 

 transfer the eggs in their mouths from the first 

 to the second hole and do this twice a day until 

 the eggs are hatched. 



If running water can be had the possibili- 

 ties of the aquarium are endless, for a ma- 

 jority of fishes can be transplanted from the 

 wild state, and kept in confinement and healthy 

 for an indefinite period. Even brook-trout 



