Should I buy it?
Hillstream Loach
Sewellia lineolata
Also known as: reticulated hillstream loach, butterfly hillstream loach, Reticulated hillstream loach, Butterfly hillstream loach
Fishori provides conservative planning guidance, not guarantees.
Based on multiple reputable aquarium care sources with strong agreement. Use the numbers here as planning defaults — your room, water, and routine still shape real-world outcomes.
A river-adapted loach that requires fast, highly oxygenated flow unlike any other aquarium fish. Still or gentle water is lethal over time.
Best for
High-flow specialised hillstream tanks with powerheads creating turbulent current and abundant algae biofilm on rocks.
Avoid if
Standard planted community setups with gentle circulation. Hillstream loaches slowly starve without the right conditions.
Top things that go wrong
- Specialist husbandry. Kept in pairs or small groups of 3 or more. Buy them at the same time rather than adding one fish at a time.
- Shrimp & snails. Shrimp: compatible in most setups. Cherry shrimp and other dwarf species coexist with peaceful small fish, though baby shrimp are food for almost any fish that gets to them.
Common mistakeStandard aquarium filtration. Hillstream loaches need at least three times standard turnover and powerhead-generated turbulence, not just a filter outlet.
What most shops don't tell you
- 1.Tropical 26°C tanks with low flow. Hillstreams want 18 to 23 °C and strong directional current.
- 2.Treating them as algae eaters in a community tank. Without biofilm and turbulent water, they starve in clean setups.
- 3.Powerheads, sponge filters, and surface agitation matter as much as volume. An unpowered nano bowl is not a substitute for a proper riffle tank.
- 4.Advanced species — research stable parameters before buying.
About this species
Rheophilic loach from cool fast oxygen-rich Asian riffles. Standard tropical community temperatures with weak flow are a common failure mode.
- Zebra Loach120L min · same group, comparable tank size
- Kuhli Loach70L min · same group, similar adult size
- Dojo / weather loach150L min · same fish family
- Yoyo Loach200L min · same fish family
- Clown Loach400L min · same fish family
- Chocolate gouramialso advanced peaceful, similar tank size
- Splash tetraalso advanced peaceful, similar tank size
No reverse lookups on file yet.
Plan grid
Key limits are shown above; this section adds planning detail: pH band, swim level, bioload and activity, and the radar.
Swim zones
Planning trait chart
Six indices for comparing species on paper before you spend.
- Beginner ease26
- Peacefulness82
- Community fit73
- Small-tank fit100
- Hardiness24
- Energy54
Numbers are deterministic planning indices from Fishori fields — not a scientific score of your individual fish.
Common setup sketches
Conservative patterns from Fishori fields — still run the pair checker for every species you add; sketches are not a stocking guarantee.
Rough 100L+ layout: one calm centrepiece, 8–12 small tetras/rasboras, 6–8 corydoras-type bottom fish — verify every name in the pair checker before buying.
Safe directions on file include: White Cloud Mountain Minnow, Pearl Danio, Zebra Danio.
Avoid “one of everything” baskets — Hillstream Loach belongs in a plan built around territory, line-of-sight breaks, and matched water chemistry.
Tank mate intelligence
Use the "Often compatible" lists as a shortlist, not a stocking plan. Always run the pair tool and check the footprint of your actual tank first. Verify behaviour for Hillstream Loach against your own reading before you buy.
Pair-level compatibility with this fish as anchor.
Read the blocking rule on each pair page before experimenting.
Do-not-stock combinations on conservative hobby rules.
Compare with
Run a real pair check: Hillstream Loach + White Cloud Mountain Minnow
Behaviour, temperament, and what to watch
Prose and lists come from the same record: read temperament first, then glass-level signals so you are not surprised after day three.
Hillstream Loach is peaceful in mixed company. Holds territory on substrate, in caves, or at the surface film. Break the sight lines with hardscape to keep the resident off the visitor.
Stress / aggression triggers on file
- Sudden crowding
- Poor water quality
Fin nipping: Not a habitual fin-nipper, but individuals can still test fins under stress or in a crowded tank.
Predation: Not a predator toward similarly-sized community fish. The usual community caveats about mouth size still apply for very small fry or shrimp.
Territory: Holds territory on substrate, in caves, or at the surface film. Break the line of sight with hardscape, and avoid placing the tank where the fish can see its own reflection.
Planted tanks: excellent — easy plant ideas
In the glass: typical and warning signs
- Moderate pacing — not hyperactive, not motionless.
- Clamped fins, gasping at the surface, hiding non-stop, or refusing food after the first week.
- Rapid breathing when parameters swing — fix ammonia/nitrite first, then reassess mates.
- Hanging in high flow or refusing open water — can mean oxygen stress or wrong current.
- Corner guarding, flaring, or body-blocking — territory is normal until it becomes relentless.
- Separate or rehome if injuries appear, one fish is pinned, or feeding becomes a daily chase.
- If water is stable but behaviour worsens, reduce stocking or remove the highest-impact species first.
Fish behaviour can vary between individuals and tank setups. Always observe new fish closely after introduction.
Care parameters: water, food, inverts, grouping
Chemistry and group rules sit here so you are not re-reading the same line from tank mate or temperament blocks. Swim level is in the plan grid above.
Hardness
medium
Diet
omnivore
Mixed diet: a quality flake or pellet as the staple, with frozen or live foods two or three times a week.
Shrimp & snails
Shrimp: compatible in most setups. Cherry shrimp and other dwarf species coexist with peaceful small fish, though baby shrimp are food for almost any fish that gets to them.
Kept in pairs or small groups of 3 or more. Buy them at the same time rather than adding one fish at a time.
Breeding behaviour depends on the species. Research before you buy a mixed-sex group of this fish.
- Hold 20 to 25 °C steadily on a real thermometer, not the dial on the heater.
- Aim for pH 6.5 to 7.5 and a hardness you can re-test in two weeks. A one-time strip in the shop car park is not a water test.
- Footprint: short wide tanks and tall narrow tanks fish differently for the same volume. Match the tank shape to the swim pattern, not just the litre count.
- Tank volume meets or exceeds 100L published minimum for adults.
- You can stock at least 3 individuals (group welfare).
- Heater can hold 20–25°C without cooking cooler-water tank mates.
- Filter maturity / stable parameters before adding sensitive stock.
Explore and stocking hubs
Same library as the rest of Fishori: tank-mate index for this species, category peers, guides, and litre-based stocking lists where min tank on file is within the hub volume.
Plan with tools
Pair-level rules and multi-fish stocking use the same conservative engine — add this fish in the tank builder only after mates pass pair checks.
Filtration & heating
A 100L minimum tank needs a filter rated for at least 400L/hr turnover and a heater to hold 20–25°C reliably.
Plant suggestions
Hillstream Loach does well in planted tanks. Plants compatible with 20–25°C and pH 6.5–7.5:
Profile status: partially verified · Evidence tier: high · 3 linked source(s). Fishori does not fabricate citations.
Fishori uses conservative planning rules based on these sources.
Confidence is explained in the summary at the top of this page (same tier as here), not repeated below.
How Fishori evaluates compatibility (same logic as pair and tank tools).
- Seriously Fish. Sewellia lineolata
Primary: aquarium size, water chemistry, behaviour, and compatibility (URL verified in upgrade script; recheck if site content changes).
- FishBase. Sewellia lineolata
Secondary: taxonomy, distribution, and maximum length in nature; cross-check with aquarium import lines and measured tank parameters.
- Wikipedia. Sewellia lineolata
Secondary: general species context; verify all husbandry numbers against a dedicated aquarium care sheet and your test kit, not a single table row.
Evidence notes
- The Seriously Fish profile for the binomial in this record was successfully reached as the primary aquarium reference.
- FishBase contributes natural-range size and habitat context. Translate those numbers through your heater, your water report, and your tank footprint before stocking.
- Wikipedia is only cited if the article URL returned OK. Use it for orientation, not as the only care sheet for an import.
- All compatibility text reflects typical hobby experience and the Fishori model. Individual fish, shop stress, and the order tank mates are added in can still defy a single-paragraph label.
- Fishori profiles work from typical aquarium trade sizes and hobby care norms. Specialist site checks and literature review for this species are not yet recorded here, so the ranges on this page are planning numbers rather than guarantees.