6 MARVELS OF FISH LIFE 



perch, now being thoroughly alarmed, raised herself off 

 the ground, erected every fin, and rapidly paled with 

 fear. For three minutes she remained in this position, 

 and then swam off, rolling her big eyes all the time, as 

 if she were on the look out for danger. 



These photographs were taken in a bright light, 

 and so the pallor on the fish is not well shown, for the 

 perch in the first photograph was already somewhat 

 light in colour. An experiment upon another perch, 

 however, better illustrates how a fish becomes pale 

 from fear. I placed a tank containing a large perch 

 upon an empty corn-bin, and left the fish undisturbed 

 for three or four hours in a dull light, at the end of which 

 time he appeared to be of a dark shade, and the bars 

 could hardly be distinguished. The corn-bin was then 

 struck three times with a hammer, and on the third blow 

 the body of the fish had visibly paled, and the bars by 

 contrast with the rest of the skin were now prominent. 



As a further manifestation of fear, it will be seen that 

 the perch is commencing to assume an attitude of 

 defence by raising the large sharp-spined fin on its back. 



An explanation as to how a fish becomes pale from 

 fear will be given later, when dealing with the subject 

 of concealing coloration in fishes. The auto-chrome 

 photograph shown on the frontispiece was taken at the 

 same time as the middle illustration of the photographs 

 to which I have referred, and is a very true rendering 

 of the colour of a perch pale with fear. 



It is unusual for the perch to remain stationary 



