It should be kept in mind that many intergrades occur between the ranges of the two subspecies. In fact, the subspecies taxon indicates merely an accumulation of minor genetic differences due to the geographic remoteness of different populations. Although the author has of yet only encountered the Grass Pickerel in a single area, a description of that habitat may prove helpful in choosing probable collecting sites and in establishing a suitable aquarium environment for specimens. The habitat to be described is judged to be successful since spawnings on at least two successive years have occurred there. Grass Pickerels have been under regular observation in this small swamp near Louisville at all seasons of the year.
Adults are most abundant in mid-summer.
The fish are found in all portions of the swamp and the small stream that feeds it. Water depth varies from three inches to about three feet. The pH fluctuates between 7.0 and 8.0, becoming more alkaline when flow through the swamp increases. The bottom is mud covered by decaying vegetation. Gambusia affinis probably makes up the major part of the Grass Pickerel's diet in this body of water.