TROPICAL AQUARIUM FISHES ‘i 
Nature the food is scarce and difficult to get. Therefore the fish have 
to exercise themselves in procuring it. In the small confines and artificial 
conditions of the household aquarium, less food can be properly digested, 
for fishes, like men, suffer from indigestion, but with quicker and more 
fatal results. Fish should never, on any account be fed more than will 
be consumed at once. (This does not apply in raising young fish.) If 
any food is left after five minutes, they have been overfed and the surplus 
should be removed with a dip-tube. (See Chapter on Aquarium Appli- 
ances.) In summer or at any time when the water is at 60 degrees or 
higher, it is allowable to feed daily. Should the water range from 55 
degrees to 60 degrees, every other day is sufficient, and when it is from 
40 degrees to 55 degrees, feedings separated by about three to six days, 
will keep them in good condition. An exact scale is difficult to establish, 
partly because fish, under one year of age, can assimilate more food than 
old ones, and partly because the temperature in an aquarium varies at 
different hours in the day. The foregoing scale will give a very good 
working basis, to be followed with a certain amount of personal judg- 
ment. Let it be said there is practically no danger of starving a fish, the 
errors being almost altogether on the other side. A correspondent once 
wrote the author that she kept a fish for seventeen years, and in that 
time had fed it on rice wafers once a week only. The matter of feeding 
fish is a difficult point to correctly impress on the mind of the general 
public. When the fish swim coaxingly to the near side of the aquarium 
it is a great temptation to feed them whether it is their meal time or not, 
but those who love their pets will do them a far greater kindness by 
depriving them until the usual feeding hour. 
Changing the Water. If for any reason it becomes necessary to 
change the water, there is one very important thing to keep in mind— 
do not subject the fishes to any sudden change of temperature, either 
higher or lower. This is one of the most frequent causes of sickness and 
eventual death. 
With the foregoing conditions carefully observed and carried out 
there should be no need to change water except at rare intervals, when the 
aquarium gets dingy looking or overcrowded with plants. Experienced 
aquarists replant about once a year, occasionally adding water to make 
up for evaporation. 
The fish are stimulated and probably benefited by changing a small 
part of the water every few days. From one-fifth to one-tenth of the 
total volume should be sufficient. If the aquarium is in proper condition 
and not overcrowded, even this slight changing of water is not necessary. 
However, it can do no harm and may do good. 
In ‘rases of overcrowding, a partial change of water should be made 
