Dace and Killifish

     When I was a boy living in the Rohrerstown area of Lancaster County, we guys would catch minnows in nets from local brooks.  Of course we did that in summer and I noticed that some of those small, lean fish had orange on them.  They were pretty and fascinating, and my introduction to local minnow-like fish in local streams and brooks of clear, running water.  I later learned those fish were breeding male black-nosed dace.   
    Black-nosed dace and banded killifish are small, (up to two inches long) streamlined fish that live in the more pristine brooks and streams in the Mid-Atlantic States, as elsewhere in North America.  They are lean to cope with water currents.  They easily swim into currents with seemingly little effort as they watch for invertebrate food to float by.  They are brown on top for camouflage above brown waterway bottoms.  In fact, they are so well camouflaged that their shadows on waterway bottoms are often more visible than the fish themselves.  Many times I am first aware of their presence because of their shadows.
     Each of these minnow-like species form pure schools of scores of themselves in the usually clear water of brooks and streams.  The dace generally congregate in "holes" of deeper water in brooks with gravelly bottoms while the killifish are more likely to inhabit shallow, slower-moving streams with muddy bottoms.  By using different niches, these fish species reduce competition for space and food. 
     Each of these fish species has beauties.  The dace have a black line on each flank from their mouths to the base of their tails.  And in summer, male dace have orange fins and an orange stripe, along with the dark one, on each side: Their breeding colors.  Killifish have several vertical, pale-blue stripes that are especially noticeable in summer, the breeding season of both these species.  And the beauties of these fish are emphasized by the clear, flowing water they live in.   
     Dace and killifish are part of food chains in the waterways they inhabit.  They eat small invertebrates at all levels of water, and are, themselves, food for trout, water snakes, belted kingfishers, a small variety of herons and egrets and other predatory creatures.
     These minnow-like fish spawn in slow sections of shallow water along waterway edges.  The dace eggs hatch among stones on the bottom of the waterways, while those of killifish hatch among aquatic vegetation in stream shallows.  Schools of the young, growing fish feed on tiny invertebrates in those shallows.         
     When along a brook or stream, watch for schools of these minnow-like fish, and their shadows, in their refreshing habitats.  They are small, but lovely fish well worth experiencing.