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 
