The Inhabitants of the Aquarium 205 



The Stickleback is an excellent aquarium 

 fish and will give great satisfaction and 

 pleasure to the amateur aquarist. It is not 

 advisable to keep it with weaker fish of a 

 quiet disposition, as it is a born fighter, ag- 

 gressive and fearless. 



The Nine-spined, or Common Eastern Stickle- 

 back (Gastcrostcus pungitius), is dark olive 

 above with dark irregular cross-bars, and 

 silvery white belly. During mating time 

 and in summer, the silvery color on the 

 belly often becomes a deep black. This fish 

 is smaller than the Three-spined, which it 

 otherwise resembles in most essential points. 

 It is common in both salt and fresh water in 

 streams and swamps along the Atlantic 

 coast. 



The Brook Stickleback (Gasterostcus incoil- 

 stans) differs in color from the others. 

 During mating time the male is jet black, 

 with red on the forepart of the body. The 

 female and the young are of an olive color, 

 mottled and dotted with black. The nura- 



