The Sri Lanka Lipstick Goby (Sicyopus jonklaasi), known locally as තොල් රතු වැලිගොව්වා (Thol Rathu Weligovwa), is a rare and striking freshwater goby endemic to Sri Lanka, belonging to the family Gobiidae. In keeping with goby family characteristics, it possesses two distinct dorsal fins and fused pelvic fins that form a sucker disc, allowing it to hold fast against strong water currents. It earns its distinctive common name from the vivid, reddish-orange lipstick-like coloration on its lips and snout, which stands out against a slender, pale brown body with subtle dark vertical bars. This delicate, bottom-dwelling species strictly inhabits pristine, well-oxygenated, fast-flowing forest streams with clear waters and rocky substrates, where it preys on small aquatic invertebrates.