72 Bean and Weed — Coloration of Fishes. 



Mississippi Valley, which has been introduced into the Potomac 

 River, shows these color changes more than any other sunfish 

 with which we are acquainted, in fact the changes of color and 

 color patterns are almost as numerous and as rapid as in the 

 angelfish. In addition to the normal color changes, an increase 

 or reduction in the intensity of the color, or a change from 

 dark to light color, due to emotions or environment, there are 

 many other changes for which we can only guess at the cause. 

 We shall probably never know why one fish when frightened 

 will turn pale while another in the same aquarium will 

 become very strongly barred. The commonest color, visible in 

 preserved specimens, in dead fish and in fish just taken from 

 the water, is a plain dark olivaceous with more or less dark red 

 in the vertical fins and with two blue lines across the cheek. 

 In the aquarium this may be seen to change to a rich golden 

 brown with or without vertical cross bars or to a plain light 

 color almost silvery. The vertical cross bars are sometimes as 

 pronounced as in the Yellow Perch ( Perca fiavescens) , at other 

 times the whole side of the fish is covered with minute shining 

 specks without any apparent regular arrangement. Any of 

 these color patterns may appear practically instantaneously. 

 The change from vertical bars to the plain coloration with light 

 specks may occur apparently in a flash. Where a few speci- 

 mens of approximately equal size are confined in a small 

 aquarium these color changes may be most readily noted. The 

 intensification in color of the largest specimen when a smaller 

 one happens to stray into forbidden territory and the sudden 

 paling of the latter as he retreats may lie seen very frequently, 

 especially when the fish are being fed. 



The Long Eared Sunfish (Lepomis auritus), known also as 

 Red Breasted Bream, is commonly a more or less yellowish fish 

 with orange spots and mottlings over the entire body, these 

 sometimes showing as more or less indistinct cross bars. There 

 are many specimens of this species in the aquarium at the 

 Bureau of Fisheries where we have watched their color changes. 

 Most of the specimens showed a dark olive color with the verti- 

 cal fins and the breast dark red. Sometimes faint cross bars 

 show. This coloration is so similar to that of Lepomis cyanellus 

 that only the position of some blue lines on the operculum and 

 the shape of the " ear ' ' indicated the specific difference. From 



