NATIVE AQUARIUM FISHES 167 



the illustration. This varies in intensity from day to day, and is brightest 

 from February until September. As these fishes dart about the aquarium 

 the flame-like appearance of the red patches is most striking. Even when 

 not in color there is an interesting bronze-green effect to the scales at the 

 lateral line. This is always visible by reflected light, and seems to show 

 mostly at night. If the light is turned on them at night they show very 

 little red color, but in a few minutes it is quite plain. 



The Rosy-Sided Dace is a large minnow, takes kindly to.the aquarium 

 and is perfectly harmless, but unless plenty of room is provided it will 

 slowly decline. Found in clear cool brooks, from the foothills of the 

 Alleghenies, from Pennsylvania to the Carolinas. 



THE BLACK-NOSED DACE 



RhinicJithys atronasus 



The Black-Nosed Dace is one of the best of our native fishes for 

 aquarium purposes. Found in abundance in small swift-running streams 



Fig. 139. The Black-Nosed Dace (Life size) 



of the Delaware Valley, and is widely distributed over Eastern North 

 America. It is an extremely active swimmer and not easily caught unless 

 cornered in a small pocket. From constant swimming against the cur- 

 rent it has developed some specialized kind of balance, so that when in- 

 troduced into the still water of the aquarium, the forward part of the 

 body continually drops so a level position is only maintained by an effort. 

 This condition disappears in a few weeks and a new equilibrium becomes 

 established. 



The Black-Nosed Dace is well rounded and full of body, the belly 

 is clear white and the black band encircling the body is quite intense. 

 It is perfectly harmless and will take almost any food. It is quite sub- 

 ject to a parasite which embeds itself deeply in the sides of the fish, pro- 

 ducing an appearance that can best be described as looking like "fly- 

 specks." This is common to many of the small wild fishes, and while 

 it is not known to have any serious results, it is unsightly. Specimens 



