VARYING COLOURS IN FISHES. 8r> 



Whether the Nuptial garb of fishes, alluded to by M. 

 Agassiz in the follo\ving sentence, has any connexion 

 with the change of food, either as to quality or quan- 

 tity, still remains to be investigated. In the Fourtli 

 Report of the British Association, this distinguished 

 Naturalist states, — " That it is during the autumn, 

 and the time of the greatest cold in the A^-inter 

 months, that the tints of the Salmonidse are most 

 brilliant, and the colours become more vivid by the 

 accumulation of great quantities of varied pigments ; 

 •so that it is almost true, that these fishes bedeck 

 themselves in a nuptial garment as do birds." 



The very singular instance before alluded to, 

 as recorded in Loudon's Magazine, evidently, we 

 think, refers to one or other of these categories. 

 The anonymous author there states, that when 

 a number of Sticklebacks are put together within 

 confined limits, a few more bold than the rest take 

 exclusive possession of a chosen district, and defend 

 it from intruders with all the valour of the Game- 

 cock. Occasional combats accordingly take place 

 between rival potentates, which terminate, if not in 

 the death, at all events, in the complete defeat of 

 one of the parties. It is in these circumstances that 

 the change of colours is observed. " An interesting 

 change takes place in the conqueror, who, from 

 being a speckled and greenish-looking fish, assumes 

 the most beautiful colours; the belly and lower 

 jaws becoming a deep crimson, and the back some- 

 times a cream colour, but generally a fine green, 

 and the whole appearance full of animation and 



