Home / Fishes / Carp, barbs, minnows, loaches / Nemacheilidae / Arrow loach
No federal permit to keepArrow loach
Nemacheilus masyae
Fishes › Carp, barbs, minnows, loaches (Cypriniformes) › Nemacheilidae (Stone loaches)
The arrow loach (Nemacheilus masyae) is a species of ray-finned fish in the genus Nemacheilus.
Intro from Wikipedia (CC BY-SA 4.0)
Care at a glance
Species-specific aquarium care
- Tank: At least 24 in long and 12 in front to back for one adult (adults commonly reach about 5.3 in / 13.5 cm).
- Water: Freshwater.
- Layout: Uses both the bottom and open water: give open swimming space plus cover near the substrate.
- Diet: A predator: feed meaty foods sized to its mouth (frozen fish, shrimp, worms); it will eat tankmates that fit in its mouth. FishBase classes it as a carnivore.
Calculated from this species' own FishBase record: tank size from its typical adult length and swimming zone, water values from its recorded ranges. The group guide below fills in general care.
Care guide
Species care notes
- Tank: a base of at least 24 × 12 in (roughly 14 US gallons); space needed is rated “modest tank”.
- Water: a fairly wide range, from slightly acidic to slightly alkaline, 73–79 °F, pH 6–7.5, 2–12 dGH.
- Behaviour: temperament peaceful; a shoaling fish best kept in a group of six or more; suited to a community tank.
- Difficulty: Moderate (Seriously Fish rating).
Short excerpts from the species profile:
- Setup: “Not difficult to maintain under the correct conditions; we strongly recommend keeping it in a tank designed to resemble a flowing stream or river with a substrate of variably-sized rocks, sand, fine gravel, and some water-worn boulders.”
- Diet: “Nemacheilus species are omnivorous although the bulk of their diet consists of small insects, worms, crustaceans and other zooplankton with only relatively small amounts of plant matter consumed, mostly via the stomach contents of prey items.”
- Tankmates: “Fishes which inhabit similar biotopes in nature constitute the best options, especially peaceful, open water-dwelling cyprinids since the presence of one or two schools can make a visible difference to the confidence of this naturally reclusive loach.”
From the Seriously Fish profile for this species, which has the full habitat, maintenance, diet, behaviour and breeding write-up 167
Stone loaches
Applies to most species in this group. Habitat: Eurasian stone loaches include oxygen-rich stream dwellers such as Schistura and small Vietnamese river species such as the hovering zebra loach. [fg157-sumo, fg157-hover]. Individual species can differ, so compare with the species numbers above and the linked sources.
Housing & setup
- For Schistura balteata groups use a floor at least 90 × 30 cm (36 × 12 in).
- Build a stream layout with sand, rounded rocks and driftwood forming numerous caves and broken sight lines.
- Use strong filtration, aeration and some flow for Schistura; change 30–50% of water weekly.
- For hovering zebra loaches use at least 60 × 30 cm (24 × 12 in), dense plants and well-oxygenated but non-turbulent water.
- Introduce hovering zebra loaches only to a biologically mature aquarium; pH 6.0–7.5 and hardness 2–12 dGH suit both profiled species.
Climate & lighting
| Water | 71.6–78.8°F |
Diet
- Small live or frozen Daphnia and Artemia.
- Bloodworms for Schistura.
- Moina, microworms and Artemia nauplii for hovering zebra loaches.
- Appropriately sized dried foods alongside invertebrates, not as the sole Schistura diet.
Social life
- Schistura defend individual caves and can harass placid bottom dwellers; groups require territories. Hovering zebra loaches are peaceful and need at least 8–10 companions.
Health watch
- Territorial fin injuries in poorly structured Schistura tanks.
- Freshwater ich, a general aquarium risk.
- Stress-associated bacterial infections.
Understanding the animal
In the wild
In the wild
From this species’ own FishBase record (habitat, bottom type, water and breeding data), not its family. Good care copies these conditions.1
| Where it lives | Lives in freshwater, in rivers and streams. Uses both the bottom and open water. Inhabits shallow depths of 2 m or less in rivers and streams with moderate current and muddy to sandy bottoms. |
| Water it lives in | Freshwater. |
| Climate | Tropical climate. |
| Wild diet | Hunting macrofauna (predator). |
Native climate (measured)
Native climate (measured)
| Warm-season highs | about 93°F (up to 96°F in the hottest sampled areas) |
| Cool-season lows | about 67°F (down to 59°F in the coldest sampled areas) |
| Average temperature | 77–81°F across sampled records |
| Relative humidity | 73–79% on average (driest month about 64%) |
| Rainfall | about 2007 mm a year, with strong wet and dry seasons |
Measured at 45 wild occurrence records sampled against WorldClim 2.1 climate data (1970–2000 averages). Air conditions in the range are ecological context, not enclosure settings: microhabitats such as burrows, leaf litter or basking rocks can be cooler, warmer or more humid.
From the sources
From the sources
Quoted from the matching sections of reputable sources for this exact species. Specialist databases are used first; Wikipedia (community-edited, CC BY-SA 4.0) only fills gaps. Other sources are short credited quotes.
| Overview | The arrow loach (Nemacheilus masyae) is a species of ray-finned fish in the genus Nemacheilus. — Wikipedia (community-edited) |
| Where it lives | Home ranges Population dynamics Growth parameters Max. ages / sizes Length-weight rel. Length-frequencies Mass conversion Recruitment Abundance Life cycle Reproduction Maturity Maturity/Gills rel. — FishBase |
| Biology | Inhabits shallow depths of 2 m or less in rivers and streams with moderate current and muddy to sandy bottoms. Occurs in forest streams flowing clear and slightly black waters, as well as in turbid waters. Feeds on insect larvae and aquatic invertebrates. — FishBase |
Data and studies
The numbers
The numbers
Each bar is what one source reports. Where several sources weigh in, the dashed gold band marks their average.
Adult length
Maximum recorded length. Measured as standard length (snout to the base of the tail, not counting the tail fin). Fish in home aquariums often stay smaller than wild records.
Water temperature
Range the species tolerates; aim for the middle.
pH
Water hardness
Minimum tank footprint
Seriously Fish recommends a tank base of at least 24 × 12 in (about 14 US gallons).
Sources for this sheet
- FishBase (Froese & Pauly, eds.), version 24.07 Peer-reviewed researchThe global scientific database on fishes, maintained by a consortium of research institutions; every value is referenced.
- Seriously Fish species profiles Experienced keeper or breederLong-running aquarium reference written and peer-checked by experienced fishkeepers and ichthyologists; each profile covers habitat, tank size, water, diet, behaviour and breeding.
- Seriously Fish: Schistura balteata Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
- Seriously Fish: Micronemacheilus cruciatus (formerly Yunnanilus cruciatus) Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
- Merck Veterinary Manual: Disorders and Diseases of Fish Zoo, university or veterinaryAdded in the 2026 source-checked care-guide review.
- Wikipedia (species article) Community referenceFree encyclopedia; useful overviews with their own citations. Intro text is quoted under CC BY-SA 4.0.
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