Taxonomy & naming
Schistura similis was described by Maurice Kottelat in 1990, part of his major revision of the Indochinese nemacheiline loaches covering Thailand, Myanmar (Burma), Laos, Cambodia and southern Vietnam. It belongs to the family Nemacheilidae, the stone or brook loaches — the largest family within the loach superfamily Cobitoidea, with well over 700 described species spread across Eurasia and North Africa.
Its genus, Schistura, is itself the most species-rich genus in Nemacheilidae, with roughly 190 recognized species and more than 100 described since Kottelat's 1990 work alone; the genus has absorbed many species once placed in the old catch-all genus Nemacheilus or Noemacheilus. The Catalog of Fishes is the standing authority for the valid name, and Schistura similis remains the currently accepted combination — there is no indication in available sources that it has been reassigned since its description.
Morphology
Schistura similis is a small, elongate loach, reaching only about 2.5 in SL at maximum, with the typical Nemacheilidae body plan: a slender, rounded-to-laterally-compressed trunk built for holding position on the bed of a current. Its most distinctive visible feature is a pattern of 7–8 very regular dark bars crossing the body, a trait FishBase specifically notes as characteristic of the species within its genus.
As in other Schistura, the skin carries only small, deeply embedded scales, leaving the fish effectively near-scaleless to the touch, and it bears the small erectile suborbital spine typical of the family — a defensive structure tucked in a groove beneath the eye rather than the showier spine of the botiid loaches. Data on fine anatomical detail is otherwise sparse; this remains a poorly studied species even by the standards of a genus in which most species are known from only a handful of specimens or streams.
Habitat
The species is recorded from the Salween basin in Myanmar, one of the major river systems draining the eastern Himalaya and the hills of Southeast Asia into the Andaman Sea. Notably, its precise type locality is not firmly documented — the original material appears to have been characterized in part from aquarium photographs rather than fully recorded field collections, which is not unusual for a genus this large and this poorly surveyed.
Like other stone loaches, it is a benthic fish of running fresh water, living on the bottom of streams and rivers rather than in still or standing habitats. Reported husbandry parameters point to cool-to-moderate, clear, well-oxygenated water — roughly 64–77 °F, pH 6.0–7.5, and soft to medium hardness — consistent with a fast-flowing hill-stream or upland river environment rather than a warm, still lowland habitat.
Feeding
Schistura similis is a benthic micro-predator, foraging over the substrate for small invertebrates — the typical Nemacheilidae diet of aquatic insect larvae, small crustaceans and other bottom-dwelling prey picked out from among stones and gravel in flowing water.
In the aquarium it readily accepts sinking prepared foods along with frozen items such as bloodworm and brine shrimp, mirroring its natural preference for meaty, bottom-delivered food rather than surface flake. A diet built around sinking pellets and frozen invertebrate foods, offered where this bottom-hugging fish can reach them without competing against faster mid-water tankmates, suits it well.
Mating
No specific courtship or spawning behaviour has been documented for Schistura similis. Data on sexual dimorphism is limited to a general note from aquarium sources that females are probably plumper-bodied when gravid, in keeping with the pattern seen across small nemacheilid loaches, but this has not been confirmed with any rigor for this species specifically.
In the related and better-observed Schistura balteata, courtship has been described as involving male displays and nudging ahead of egg release, but there is no confirmation that Schistura similis follows the same pattern in captivity or the wild. Given how little of the genus has been studied in this respect, the honest position is that mating behaviour in this species is essentially unrecorded.
Breeding
Schistura similis is not known to have been bred in captivity. As in other stone and brook loaches, the expected mode is an egg-scatterer over gravel and among stones in fast-flowing water, with no parental care of eggs or fry — but this has not been directly observed or documented for the species itself.
Aquarium sources for the genus more broadly describe related Schistura as extremely difficult to spawn at home, and virtually all specimens in the trade are wild-caught rather than tank-raised. There is no farm-production pathway for this species as there is for high-volume botiids like the clown loach; anyone keeping it should expect to enjoy a wild-collected fish, not to breed it.
In the aquarium
Schistura similis is a modestly sized loach — around 2.5–3 in — that wants the classic stone-loach setup: cool-to-moderate, clean, well-oxygenated water with real current, soft-to-medium hardness, and a bed of large pebbles and slate arranged into piles and crevices for cover. It is territorial and benthic, so multiple hiding places matter even in a modest-sized tank, and it should not be crowded with delicate or slow tankmates given its readiness to defend a patch of substrate.
As with other nemacheilids it is essentially scaleless and correspondingly sensitive to copper-based medications and full-strength treatments generally — half-doses and gentle products are the safer approach if disease treatment becomes necessary. Feed it sinking foods after the more boisterous fish have had their fill, keep the water moving and well-oxygenated, and treat it as a specialist stream fish rather than a generic bottom-dweller.
Conservation
Schistura similis has not been formally assessed by the IUCN and is Data Deficient in FishBase's summary as of 2011. This reflects the reality for most of its huge genus: hundreds of Schistura species are known from one or a few streams, with limited biological, ecological or population data available in the scientific literature, making a meaningful conservation assessment difficult.
There is no documented population trend or specific threat data for this species. As with many range-restricted Salween-basin stream fishes, the general pressures facing the region — deforestation, damming and water-quality change in the wider Salween drainage — are plausible long-term concerns, but no source consulted here quantifies any impact on Schistura similis specifically, and the trade in this species (where it occurs at all) appears to rely on wild collection rather than any commercial breeding program.