FEESH-WATEE AQTJAEIA. 



proportion to its superficies, but also because the act of their 

 swimming agitates the surface of the water, thus helping to 

 aerate the whole of it ; and for the same reason the twenty- 

 six minnows lived for a week, and would have done so 

 longer, in an ordinary soup-plate half-full of water. 



Of com-se, an aquarium ought not to be so shallow that 

 the water-plants wiU faU to grow properly. A tank may be 

 of almost any depth, but it must have length and breadth in 

 proportion. To sum up, in order that an aquanum may 

 be a success, it is necessary that it should be of the right 



shape; that the repre- 

 sentatives of the Animal 

 Kingdom should not be 

 in excess of the mini- 

 mum amount of weed ; 

 and that a little oare 

 be taken daily to main- 

 tain their balance. 



It is almost unneces- 

 sary to say that if an 

 aquarium is taken up as 

 a toy, to be fussed over 

 for a few days and then 

 to be neglected for 

 weeks, it will be any- 

 thing but pleasing and 

 instructive. The water under these circumstances will 

 quickly become corrupt and offensive, many of the animals 

 win die, those which are unfortunate enough to survive will 

 be extremely miserable, and the owner and his friends will 

 come to the conclusion that an aquarium is certainly not 

 what I have described it to be — both pleasing and instructive. 

 There are very many kinds of aquaria, ranging from the 

 simple, flat earthenware pan, to the beautiful and expensive 

 combination of plate-glass, slate, fountains, enamel, and 

 gilding. All are more or less useful. The aquarium, of 

 course, most suitable for the fish and the plants is that 

 which most resembles a pond — the light only entering it 



Fig. 4. 



