184 NORTHERN FISHES 



in all parts of INIinnesota, including the Red River and the Lake Supe- 

 rior drainage. Greene (19.'55) reported it to be widely distributed over 

 Wisconsin. It is fond of muddy streams and pools with aquatic vegeta- 

 tion. Loving muddy bottoms and living in the mud as it does, it is no 

 doubt often overlooked. It may be mistaken for the young of the dog- 

 fish, Amia calva, which it closely resembles in color and shape. How- 

 ever, it can always be recognized by the short dorsal fin, for in the 

 dogfish the dorsal fin extends almost to the caudal fin. The mud- 

 minnow is carnivorous; it feeds on small Crustacea, worms, and in- 

 sects. It has the interesting habit of quickly concealing itself when 

 frightened by wriggling downward into the bottom mud, tail first. 

 It is very hardy. It has the habit of burrowing into the mud when the 

 water in a pond evaporates. For this reason it is often the only fish 

 inhabiting swamps, shallow ponds, and bog pools. It is very common 

 in ditches in some of the swamps and muskegs of northera Minnesota. 

 Mudminnows spawn in the spring; ripe females have been found in 

 the middle of April. They are reported as migrating up small streams 

 and depositing their eggs singly on the leaves of aquatic plants. 



