26 PRINCIPLES OF THE AQUARIUM. 



little common sense exerted in its arrangement cannot 

 fail to ensure the perpetual comfort of its inhabitants. 

 There are few " hobbies " which require less trouble, 

 and as a rule it will be found that whatever "trouble" 

 is caused, is due to ignorance, in not understanding 

 the habits of aquatic animals and plants and the con- 

 ditions under which they best thrive. 



But, it may be asked, how are we to know all about 

 such matters, unless we gain experience by first keep- 

 ing aquaria ? This is very true, but unfortunately 

 a great many people do not persevere in keeping 

 them, but exchange them for some other amuse- 

 ment as soon as difficulties arise. Perhaps they have 

 not understood the elementary principles on which 

 a streamless aquarium should be constructed, and so 

 in putting it together wrongly they have been laying 

 up for themselves an endless store of trouble. Or 

 they have not taken the slightest pains to understand 

 whether the animals and plants they have placed in 

 the water were likely to agree there. An aquarium 

 thus stocked has looked well up to the evening of the 

 same day, but next morning it has presented all the 

 appearance of a field of battle. In the darkness of 

 the night, or rather in the early morning, a dire con- 

 flict has taken place. Each animal has been battling 

 with its fellow, the weakest has gone to the wall, and 

 only a few gorged cannibals remain of the too large 

 stock with which the aquarium was peopled the day 

 before ! These are eyeing each other with suspicious 



