RECAPITULATION. 303 



3. An aquarium cannot do well, without a great deal of 

 unnecessary trouble, unless it be properly situated. The 

 sun should never be allowed (except under special circum- 

 stances, which have already been referred to) to shine, directly 

 upon the water of it : and a north aspect is the best. 



4. Unless it be very small, an aquarium should be placed 

 in the position in which it is intended to remain before it 

 is filled with water. Any attempt to remove a fairly-sized 

 tank when full of water will be certain to do some, if not 

 great, harm to the vessel or its contents. 



5. Everything, whether gravel or sand, or water or weed, 

 which is placed in the aquarium should be perfectly clean. 



6. The aquarium ought always to be fiUed with water by 

 means of one or more small siphons. 



7. All aquaria, with very few exceptions (which have already 

 been mentioned), should contain aquatic plants. These plants 

 ought, of course, to be healthy, of the right kind, and set in 

 the right way. Vallisneria spiralis is one of the best of all 

 plants for this purpose. 



8. All aquatic animals should be wisely associated. No fish 

 or any other animal ought to be allowed to molest its 

 companions. 



9. No strange fish, especially a fish purchased, should be 

 introduced into a tank tmless it has been for some time in 

 quarantine. The introduction of an unhealthy fish is almost 

 certain to be the cause of considerable loss. All gold-fish 

 procured for the aquarium should be those known as '' cold- 

 water" fish. 



10. Aquatic snails ought to be judiciously chosen; that is, 

 those univalves which feed upon confervas and decaying vege- 

 table matter should be preferred to those which eat healthy 

 and growing plants. The Planorbes, as a rule, are the best 

 for aquarium purposes. 



11. Carnivorous and herbivorous beetles should never be kept 

 in the same vessel. 



12. No animals should be expected to live without food ; nor 

 ought animals to be tempted to prey upon each other through 

 lack of a sufficiency of food. 



