Haplochromis vonlinnei is a moderate-sized, slender cichlid with an acute snout, slightly protruding lower jaw and curved teeth.

In the male, the anal fin is grey with two to four bright orange circular spots with thin white rims (egg dummies).

[3] Among other fish in the genus Haplochromis found in Lake Victoria, it is similar in shape to H. pyrrhopteryx but differs in colouring as that species lacks a mid-lateral band.

The IUCN has listed Haplochromis vonlinnei as being "Critically Endangered" and suggests it is either exceedingly rare with very few individuals remaining, or may already be extinct.

[1] Another factor that may affect any remaining fish is the diminished clarity of the water which may make mate recognition more difficult.