THE FHESII-WATEK AQUARIUM. 91 



should l)c kept is, also, a matter of great importance, for 

 if wc once allow it to get too low, the water freezes, our 

 vessel bursts and then farewell to all our pets ; and if 

 wc allow it to get too warm we shall lose both plants and 

 animals by a system of slow boiling. Sixty degrees of Fah- 

 renheit's scale is about as high as we should allow the 

 temperature to rise. In summer, we should, therefore, 

 shade the tank most part of the day from the direct 

 rays of the sun by means of ground glass or a white win- 

 dow blind or oiled paper. And in winter, if we have 

 it in a room where there is a blazing coal fire, or, worse 

 still both for man and beast, a heater of a furnace, wc 

 shall find that though the warmth may be pleasant to us, 

 it will be decidedly uncomfortable for our fish, who arc 

 not used to being shut up in houses. To remedy this we can 

 place it near the window, which will, most likely, be the 

 coolest part of the room, or even open the window. A 

 little fresh air blowing on the surface of the water, if it 

 be not too cold, is good at all seasons for both plants 

 and animals. I generally keep a thermometer immersed in 

 the water of my tank, by means of which I can judge of 

 the temperature and tell when I should minister to the 

 well-being of my fish. Mr. Ilibbcrd recommends in sum- 

 mer when the water of the tank has become unduly 

 heated by the sun's rays, to wrap around it a coarse cloth, 

 saturated with water, and to keep this wet from time to 



time. 



Remember, that dead and sick animals should be removed 

 as soon as discovered. Fish are apt to become diseased in 

 winter aud are troublesome to cure. Somotimes the caudal 



