What is Sewellia lineolata's temperament like?

It's a peaceful fish that rarely bothers tankmates. It spends much of its time clinging motionless to rocks rather than swimming actively around the tank.

Is this loach suitable for beginners?

It's generally rated as suitable for intermediate keepers, since it needs equipment that can maintain strong water flow and high oxygen levels. It's best to gain some basic aquarium experience first.

How big does it grow?

Adults typically reach about 5.7 to 6.5 cm. Its flattened body is wider than it looks at a glance, so it stands out in the tank.

Among loaches, this species is considered relatively easy to breed. That said, success still depends on maintaining its specific requirements, like strong water flow, so it helps to research in advance.

Is this species regulated under CITES?

Sewellia lineolata is not listed under CITES.

Reticulated Hillstream Loach

Sewellia lineolata, the Reticulated Hillstream Loach, is known for its flattened, sucker-like body that clings firmly to rocks in fast-flowing water. Its striking yellow-and-black reticulated pattern makes it stand out in any aquarium. Because it comes from swift mountain streams, it does best with strong water flow, high dissolved oxygen, and algae-covered rocks to graze on. It's generally peaceful toward other fish and works well alongside calm tankmates. Keeping one takes a bit more setup knowledge than average, so it's usually recommended for intermediate aquarists — but among loaches, it's considered one of the easier species to breed, making it a rewarding project for anyone hoping to recreate a slice of stream habitat at home.

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Reticulated Hillstream Loach key facts

Care level: Intermediate
Lifespan: 5-8 years
Size: 5.7-6.5cm
Temperature: 20〜24℃
Diet: Benthic algae, home-made vegetable-rich foods, algae-based dried foods
Tank: Seriously Fish suggests a 75 x 30cm base of about 68 litres. Use rounded river gravel and stones, and create a turnover of 15 to 20 times per hour. Keep the lighting strong to grow algae.
Water Temperature & Quality: Seriously Fish gives 20-24C, pH 6.0-7.5 and 1-10dGH. Clean, well-oxygenated water is essential, and it suffers in warm or poorly oxygenated tanks.
Tank Mates: It suits fish from the same stream habitats, such as small cyprinids, Rhinogobius and Stiphodon gobies and rheophilic catfishes. Avoid similarly shaped, less bold gastromyzontids, which lose out in competition for food.
Diet & Feeding: Its staple is benthic algae and micro-organisms. Home-made foods bound with gelatin and rich in vegetables or Spirulina work well. If algae are short, grow them on rocks in a separate tank and rotate the rocks in.
Breeding & Spawning: Seriously Fish calls it arguably the easiest of all loaches to breed. A deep bed of large, rounded river gravel gives the eggs crevices in which to be protected.
Health & Notes: Avoid new driftwood, which leaches tannins that discolour the water and hinder algae growth. IUCN status is Vulnerable.

TraitsLoachFreshwater fishRheophilicIntermediate

About Reticulated Hillstream Loach

Sewellia lineolata (Reticulated Hillstream Loach) is a stream-dwelling loach with striking yellow-and-black reticulated markings. It clings to rocks and thrives with strong water flow and plenty of oxygen — a pick for intermediate keepers.

7 things to know before welcoming a Reticulated Hillstream Loach

1Needs Strong Flow and Oxygen
As a stream-dwelling loach, Sewellia lineolata needs strong water flow and high dissolved oxygen in the aquarium. Use a powerhead or a canister filter's outflow to recreate these conditions and prevent low-oxygen stress.
2Provide Rocks to Cling To
With its flattened body, this loach clings to rocks and glass. Add plenty of rocks and driftwood as footholds and hiding spots so it can settle in comfortably.
3Grazes on Algae
In the wild it grazes algae off rocks, and it will do the same in your tank. Supplement with sinking algae wafers to help keep its diet balanced.
4Keep With Calm Tankmates
Sewellia lineolata is peaceful and rarely aggressive, but it's a slow-moving bottom dweller. Fast, competitive fish can outcompete it for food, so choose calm tankmates.
5Sensitive to Water Changes
Coming from oxygen-rich mountain streams, this loach is sensitive to high temperatures, low oxygen, and sudden shifts in water quality. Keep summer temperatures in check and change water regularly.
6Best for Intermediate Keepers
This species is generally considered suitable for intermediate keepers who understand flow and filtration needs. First-time aquarists may want to get comfortable with basic tank management before taking one on.
7Set Up the Tank Before Arrival
Have strong water flow and oxygenation equipment running before bringing one home. Adjust your filter outflow and aeration in advance to mimic a stream environment.

Frequently asked questions about Reticulated Hillstream Loach

Q.What is Sewellia lineolata's temperament like?: A.It's a peaceful fish that rarely bothers tankmates. It spends much of its time clinging motionless to rocks rather than swimming actively around the tank.
Q.Is this loach suitable for beginners?: A.It's generally rated as suitable for intermediate keepers, since it needs equipment that can maintain strong water flow and high oxygen levels. It's best to gain some basic aquarium experience first.
Q.How big does it grow?: A.Adults typically reach about 5.7 to 6.5 cm. Its flattened body is wider than it looks at a glance, so it stands out in the tank.
Q.Is it easy to breed?: A.Among loaches, this species is considered relatively easy to breed. That said, success still depends on maintaining its specific requirements, like strong water flow, so it helps to research in advance.
Q.Is this species regulated under CITES?: A.Sewellia lineolata is not listed under CITES.