60 AMPHIBIANS AND FISHES. 



against all spawn-loving fish, until such time as it is 

 hatched. Even then the labour is not over, for we 

 may see the paternal fish hovering about the young 

 fry with the greatest anxiety, and valiantly running 

 tilt against all other animals, those of their own spe- 

 cies included, who may be desirous of making further 

 acquaintance with them. The commonest of these 

 little fish is the rough-tailed or three-spined stickle- 

 back (Gasterosteus trachnrus). The male will attack 



Fig. 18. 



Rough-tailed Stickleback (Gasterosteus trachitnts). 



anything that comes near his nest, even the carnivorous 

 water tigers and water beetles. Another species is 

 Gasterosteus semi-armattis, very common in some 

 streams and rivers, and this also constructs a nest, 

 and generally adopts the habits above described. 



Nearly allied to the sticklebacks in many respects 

 is the Miller's thumb, or river bull-head (Cottns 

 gobio}. In many rivers they are very abundant, so 

 there is no difficulty in procuring them. In the 

 aquarium they are active and wary little animals, 

 loving to hide under the loose stones. 



The loach (Cobitis barbatula) is another interesting 

 little fish that may be readily domesticated. As its 



