FISHES. 149 



large dimensions, and ought to present a great surface of 

 water in proportion to its size ; it must also contain a qjiantity 

 of growing aquatic plants. But Trout, however weU they may 

 be cared for, and however stdtably the aquarium in which they 

 are confined may be constructed, will lose a great deal of the 

 beauty and brilliancy of their colouring. There are, perhaps, 

 no fish whose colouring and form ai-e influenced so much by 

 food and locality as Trout. For instance, it has been said 

 that "the Trout of Lynn Ogwin, almost the whole bottom of 

 which is formed of grass, have, when first caught, a brUliant 

 emerald gloss over their golden and yellow tints." And if the 

 bottom of the water in which Trout live is black, the fish will 

 be very dark. Sometimes, when the same lake or river varies 

 in character as to the bottom soil, the Trout taken from the 

 same water, but from different parts of it, will also vary in 

 colour. That it does not take long for a Trout to change the 

 shading of his colouring, may be easily proved by placing a 

 captured fish for a few minutes only in a large white basin of 

 water, and he will be seen to grow pale under the influence of 

 the colour with which he is surrounded. However, I believe 

 that any fish will alter the shading of its colours imder similar 

 circumstances. I can remember my astonishment when I first 

 saw an instance of this chameleon-like power on the part of 

 fish. A good many years ago I had asked a Thames profes- 

 sional fisherman to net me some gudgeon for an aquarium. 

 A day or two after I had made the request he brought me 

 the gudgeon, but more than my tank could conveniently hold. 

 However, not wishing to send them back, in case some of 

 those which I had retained for the aquarium should die, I 

 placed the surplus fish (for the time being) in a large sponge 

 bath. There they remained for more than a week, and at 

 the end of that time they had become almost white. Since 

 then I have often had occasion to keep fish temporarily in a 

 bath (not half a bad receptacle for them), and have not failed 

 to notice the great influence which the white interior has had 

 upon the colouring of the different species of fish — a black 

 bass, for instance, becoming in a day or two anything but 

 a black bass in appearance. ' 



