actual consumption. If an aquarium is in such a place as to be affected by seasonal temperature 

 changes, the fish should be given food less frequently and in smaller quantity' during the colder months. 



Food may be scattered over the surface and allowed to fall to the bottom, or it may be placed in a 

 little tray or dish suspended a few inches below the surface. The advantage of the former method is 

 that the fish have to seek their food and take it more slowly; the disadvantage is that the unconsumed 

 food is not easily removable and the amount can not readily be estimated. The advantage of the latter 

 method is the fish may be more closely watched when feeding, the proper amount of food can be 

 more accurately determined, and the unconsumed food is not left to pollute the water and can be easily 

 removed. 



A nicely balanced aquarium requires but little attention. So long as the water remains pure, 

 no change is necessary; some of the most successful aquaria go for several years without a complete 

 renewal of the water; and all that is required is to replace the water lost by evaporation. When 

 water becomes foul through neglect or ignorance, the fish should be removed to another vessel, the 

 plants thoroughly washed in running water, and the aquarium emptied, cleansed, and filled with pure 

 water. When oxygenation is imperfect and the fish are suffering (as shown by their' restlessness, 

 evident discomfort, labored respiration, and efforts to get air at the surface), the water may be aerated 

 by dipping it up and pouring it back from a height of a foot or more, fiesh water may be introduced, 

 and a more adequate plant growth should be provided. It is necessary to cleanse the sides of the 

 aquarium of algal and other growths from time to time, in order to afford a good view of the fish. 

 Accumulations of animal and vegetable waste matter on the bottom must be removed frequently- 

 preferably each day; this is done most conveniently by means of a glass tube about half an inch in 



102 



