SICKL Y AQUA RIA . 29 



little consideration, and perhaps because people could 

 not resist the temptation to have as many animals in 

 the aquarium as possible. There is one sure rule of 

 guidance to a beginner in these matters have too 

 few animals rather than too many. They will com- 

 pensate for numbers in the sense of health they seem 

 to enjoy, in their vivacious gambols, and sprightly 

 habits. The fishes are here, there, and everywhere, 

 instead of always gasping with open mouths on the 

 surface of the water.* The newts are frolicking about, 

 or basking on the surfaces of the leaves and stones. 

 Still, although we give this advice, it is to be followed 

 with a degree of caution, for the over-stocking of an 

 aquarium with plants is liable to overthrow the 

 balance of life with almost equally fatal results. If 

 there are too many plants the principle of natural 

 selection soon sets in ; the weakly or badly adjusted 

 species die off; the water becomes foul, and perhaps 

 assumes a thick green hue. There is a ready means of 

 checking such a disaster, however, for the evil re- 

 sulting to an aquarium from excess of plant growth is 

 not so rapid in its effects as when it is over-crowded 



* Mr. W. A. Lloyd has produced twelve practical articles on Aquaria 

 in the following numbers of ' Cassell's Popular Recreator,' published in 

 1873 and 1874 : 4, 8, 12, 16, 20, 24, 30, 32, 35, 38, 41, and 45. They 

 are illustrated by fourteen woodcuts, of which eight are especially valu- 

 able as representing, drawn to an accurate scale, how many creatures, 

 and of what kinds and sizes, can be maintained in aquaria of a named 

 water capacity, of a given water distribution as to surface, and at a 

 given temperature. 



