The blackspotted topminnow is a sleek, swift fish with a slender, elongated shape. Topminnows have a habit of skimming along just beneath the surface of the water, so the top of the head and forward part of the back are broad and flat, and the mouth is tilted upward so it opens at the upper surface of the head. The body is long, there is no lateral line, and the single dorsal fin is located far back over the anal fin. The tail fin is rounded. None of the fins have spines.
This particular species is light brown, with a velvety black longitudinal stripe running from the tip of the snout through the eye to the base of the tail fin. It is distinguished from its cousin, the blackstripe topminnow, by having upper sides with few to many black spots that are regular in outline and that are about as dark as the stripe along the midside.