180 MARVELS OF FISH LIFE 
weighing just under half a pound. Water ran through 
this tank night and day, and the glass was shaded 
from the sun except when it was removed two or 
three times a day, so as to get the fish accustomed to 
being suddenly surrounded by bright light. 
At the end of a week I put some minnows in the 
tank; but the perch would not take these and so they 
were removed. The minnows were offered to the 
perch every day during the next week with the same 
result. At the end of a fortnight the perch took a 
minnow, and after that he fed fairly freely. He then 
became comparatively tame, and I obtained several 
photographs, three of which are shown. 
My reason for removing the food unless the fish 
took it was that the perch would have become accus- 
tomed to wait until he was left alone before he fed, 
and I should never have had an opportunity of obtain- 
ing photographs illustrating many interesting attitudes 
which are connected with the feeding of a fish. 
When a fish refuses to feed for a considerable time 
I turn him free and start again with a fresh one, for fish 
vary very much in temperament. One will be per- 
fectly tame in a tank in a month or six weeks, whereas 
another will never get accustomed to such surroundings, 
and in consequence he does not feed, and will die of 
starvation unless released. 
The photographs illustrating the nesting of the 
sticklebacks were only obtained after three years’ 
work, for the fish, though they nested, would never 
