Reticulated Hillstream Loach

Sewellia lineolata

Loaches

A fascinating, highly specialized loach adapted to fast-flowing, oxygen-rich rapids. They have a flattened, ray-like body allowing them to cling to smooth rocks where they graze on algae and biofilm (aufwuchs). They strictly require strong water flow, high dissolved oxygen, and cooler temperatures. Males frequently engage in visually striking but harmless territorial 'battles' over prime feeding rocks.

At a Glance

Adult Size6.5 cm
Body ShapeDepressed
Growth RateSlow
TemperamentMostly Peaceful
Water TypeFreshwater Only
Flow PreferenceHigh
Waste OutputLow
StockingGroup of 3+

Tank Requirements

Minimum Volume80 L
Minimum Length90 cm
FlowHigh
Water TypeFreshwater Only
Must-Haves in the Tank
Smooth Gravel (Sensitive Barbels)Established Algae (Otocinclus)Plants - lighly covered

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Water Parameters

Temperature2024°C
pH6.57.5
Hardness415 dGH

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Temperament & Compatibility

Aggression LevelMostly Peaceful
3/10
Where They Swim
Surface
Mid-level
Bottom
Stocking Guidelines
Keep at Least3 fish
Max per TankNo limit
Can Live Alone?No — needs a group
Behavior Traits
Hyperactive / Fast SwimmerTerritorial (Defends specific area)

Available Varieties

Each variety inherits the species defaults above. Only differences are highlighted.

Standard

The standard wild-type Reticulated Hillstream Loach. To thrive, ensure a unidirectional flow setup (river manifold) and plenty of smooth river rocks illuminated by strong light to promote algae growth.

Same care requirements as the base species

Also known as: Wild Type

Reticulated Hillstream Loach Care Guide Summary

The Reticulated Hillstream Loach, scientifically known as Sewellia lineolata, belongs to the Loaches family group. Adults reach a maximum size of approximately 6.5 cm and have a depressed body shape with a slow growth rate. Classified as mostly peaceful, this species primarily occupies the bottom zone of the aquarium and produces a low level of biological waste.

To thrive, the Reticulated Hillstream Loach requires a freshwater only aquarium with a minimum volume of 80 litres and a tank length of at least 90 cm. Water temperature should be maintained between 20°C and 24°C, with a pH range of 6.57.5 and a general hardness of 415 dGH. A high water flow is preferred. An aquarium test kit can help you monitor these values.

Due to its specialist needs, the Reticulated Hillstream Loach is best suited for fishkeepers who can provide a carefully planned setup. The Reticulated Hillstream Loach is typically available in one standard form.

Reticulated Hillstream Loach Habitat Setup

When setting up an aquarium for the Reticulated Hillstream Loach, a high water flow best suits their natural preferences. Because this species occupies the bottom zone, the aquarium layout should prioritise sufficient floor space with hiding spots among rocks, wood, or dense planting. Useful additions include smooth gravel or rounded substrate to protect their sensitive barbels, an established tank with natural algae growth, as they depend on it as a primary food source, and light plant coverage for partial shade. Browse smooth aquarium gravel options to find the best fit.

Reticulated Hillstream Loach Compatibility Notes

Classified as mostly peaceful, the Reticulated Hillstream Loach is a social species that requires the company of its own kind to thrive. When choosing tankmates, territorial behaviour may cause issues if hiding spots or floor space are limited and their energetic swimming style may stress more sedentary or timid species. Selecting tankmates that favour different water layers from the bottom zone can help reduce competition and territorial overlap.

Recommended Tank Sizes

Standard aquarium sizes that meet the minimum volume and length requirements for Reticulated Hillstream Loach.

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Frequently Asked Questions About Reticulated Hillstream Loach

How big does Reticulated Hillstream Loach get?

Reticulated Hillstream Loach (Sewellia lineolata) typically reaches a maximum adult size of approximately 6.5 cm. They have a depressed body shape and a slow growth rate.

What tank size does Reticulated Hillstream Loach need?

A minimum aquarium volume of 80 litres and a tank length of at least 90 cm are recommended for Reticulated Hillstream Loach. This ensures enough swimming space and helps maintain stable water conditions.

What water parameters does Reticulated Hillstream Loach need?

Reticulated Hillstream Loach thrives in freshwater only conditions with a temperature range of 20–24°C, a pH between 6.5 and 7.5, and a general hardness of 4–15 dGH. A high water flow is preferred.

Is Reticulated Hillstream Loach peaceful or aggressive?

Reticulated Hillstream Loach is classified as mostly peaceful with an aggression score of 3 out of 10. They are generally well-suited to peaceful community tanks.

Can Reticulated Hillstream Loach live alone?

No, Reticulated Hillstream Loach should be kept in groups of at least 3 to reduce stress and encourage natural behaviour.

Does Reticulated Hillstream Loach have any special tank requirements?

Yes. Reticulated Hillstream Loach benefits from smooth gravel (sensitive barbels), established algae (otocinclus), and plants - lighly covered in the aquarium. These features help replicate their natural habitat and promote overall health and well-being.


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