Taxonomy & naming
Lentipes crittersius is a true goby of the family Oxudercidae, placed in the Sicydiinae, the amphidromous stream gobies of Indo-Pacific islands. The Catalog of Fishes lists it as valid under the authority Watson & Allen, 1999. The type locality is given there as: Aiyindor Creek, Biak Island, Irian Jaya, Indonesia.
Morphology
Sicydiine gobies have the pelvic fins fused into a cup-shaped sucker disc, which lets them hold position on rock in fast current and climb wet rock faces on the way upstream. Males in this group are usually more colourful than females. FishBase gives a maximum of 1 in SL, based on a female. A detailed colour description has not been compiled here.
Habitat
FishBase lists the species as freshwater and benthopelagic and records it from Irian Jaya, Indonesia. The type series was collected above a series of waterfalls, alongside Sicyopus discordipinnis and Stiphodon birdsong. Like other sicydiines it is a fish of clear, fast, well-oxygenated water. Measured water chemistry has not been published.
Feeding
Lentipes species are generally regarded as carnivores that take small invertebrates and insect larvae from the stream bed. The diet of this species has not been described specifically.
Mating
Mating has not been described for this species. In better-studied sicydiines, males hold small territories on stream rock and court females at a nest site.
Breeding
Sicydiine gobies are amphidromous: eggs are laid in fresh water, the larvae drift to sea, and the post-larvae return to rivers months later. Details specific to this species have not been published. It cannot be assumed to breed in a closed freshwater aquarium, and trade fish are wild-collected.
In the aquarium
Species in the trade under this name are demanding. They need cool to moderate, very clean, strongly oxygenated water, brisk flow, rock surfaces with mature biofilm, and a tightly closed lid. Husbandry for Lentipes crittersius itself has not been documented, so general sicydiine practice is the only guide. Identity of fish sold under this name should be treated with caution.
Conservation
The IUCN assessed Lentipes crittersius as Least Concern in 2019, meaning it is not currently considered at risk. Like other amphidromous gobies, it depends on unobstructed streams down to the sea, and dams, weirs and stream degradation are threats to the group.