Nemacheilidae

Ceylon Loach

Schistura notostigma

Schistura notostigma, commonly known as the Ceylon loach, belongs to the family Nemacheilidae (river loaches). This fish is endemic to the island of Sri Lanka, formerly known as Ceylon. Its natural habitat is fast-flowing mountain streams, where it prefers shallow areas with a stony bottom.

Tank
from 80 L (21 gal)
Temperature
20 – 24 °C (68 – 75 °F)
Size in aquarium
6 – 6.3 cm (2.4 – 2.5 in)
Acidity
pH 6–8
Natural rangeRange on the map
  • Central Highlands area
  • Sri Lanka

Tank conditions

Plan the tank stocking
Temperature
20 – 24 °C (68 – 75 °F)
Water pH
Slightly acidic (6) – Slightly alkaline (8)
Water dH
Soft (5) – Hard (15)
Water salinity
no salt (freshwater)
Size in aquarium
6 – 6.3 cm (2.4 – 2.5 in)
Lifespan
4 years
Temperament
Aggressive Aggressive / incompatible / unfriendly
Toward small fish
not a predator
Required aquarium volume
from 80 L (21 gal)
Lighting
any
Substrate
rocky rock formations, boulders, etc.
Water flow
moderate or strong
Feeding
Sinking (any)
Keeping
Small group 3–4 individuals
  • Lifespan. A lifespan to expect under good care, not a measured value: it depends heavily on tank volume, water quality and diet — and for selectively bred forms, on their origin as well.
  • Toward small fish. Based on the Predators category in the catalog or the temperament in the species parameters. “A risk to small fish” means the species is not a predator by habit, yet will swallow any fish that fits in its mouth.
  • Required aquarium volume. This is a husbandry recommendation, not a measured value: the volume depends on the keeping mode (small group (3–4 individuals)), footprint, decor and tank mates.

Care and keeping

Description

Adults of this species reach approximately 6 cm in length. The fish has an elongated, slightly cylindrical body, with a small head and short fins. The coloration consists of a series of dark vertical bands alternating with a gray or yellowish background on the back. A distinct, contrasting black band runs at the base of the tail.

Habitat

The species is endemic to Sri Lanka. It inhabits fast-flowing mountain streams with a stony or gravel bottom. It prefers shallow waters with high dissolved oxygen content and strong currents. In nature, the fish are often found in areas with clean, clear water, where they move among stones and pebbles.

Behavior and Compatibility

This fish has a rather temperamental and quarrelsome nature. In small aquariums, territorial skirmishes are inevitable and can be quite fierce. Despite this behavior, the Ceylon loach needs the presence of conspecifics. For small tanks (80–100 liters), it is recommended to keep a group of 2–3 individuals. Conflicts can arise not only between conspecifics but also with other species, especially bottom dwellers. Suitable tank mates include fish that inhabit the water column or surface, capable of tolerating moderate to strong currents.

Care and Maintenance

The optimal aquarium volume for keeping a group of 2–3 fish starts from 80–100 liters. In terms of decor, attention should be paid to the bottom layer, as loaches are benthic. Coarse-grained sand combined with stones, boulders, and driftwood is suitable for the substrate. Among aquatic plants, unpretentious species that can attach to hard surfaces are preferred, such as Anubias, Bucephalandra, as well as various mosses and ferns, as they do not require rooting in the substrate. The Ceylon loach, originating from mountain rivers with strong currents, prefers similar conditions. Therefore, it is important to ensure sufficiently strong water circulation in the aquarium, using a separate pump or a high-performance filtration system. Long-term success largely depends on the aquarist's ability to maintain clean, oxygen-rich water and relatively low temperatures, not exceeding 24°C.

Diet

Fish can be accustomed to dry sinking foods, such as flakes or granules, although they show a clear preference for live food, such as bloodworms.

Breeding and Reproduction

Reliable information on the breeding of Schistura notostigma in aquarium conditions is not available. Scientific literature notes that sexually mature individuals of this species require specific conditions, as close as possible to natural mountain streams, but successful cases of offspring production in captivity have not been described.

Diseases

Specific diseases for this species have not been described. The main factor for health is maintaining high water quality and sufficient aeration. Fish are extremely sensitive to low oxygen levels and the accumulation of organic waste, which, under poor keeping conditions, quickly leads to a weakened immune system and the development of bacterial infections.

How to choose

When choosing, pay attention to the fish's activity: healthy individuals are constantly moving, exploring the substrate, and have a robust physique without signs of emaciation. Avoid specimens with damaged fins, body film, or sunken bellies. Given that the species often comes into sale as bycatch with other loaches, it is important to ensure correct species identification.

Compatibility

There are no pair reviews for this species yet — check tankmates in the matcher.

All tankmates

Plants and this fish

Matching water does not mean the plant will stay intact.

Frequently asked questions

The essentials: size, tank volume, water parameters and care

How big does Ceylon Loach get?

An adult reaches 6–6.3 cm in length. Plan the tank around the maximum size: the fish quickly outgrows a cramped setup.

What size aquarium does Ceylon Loach need?

The recommended volume is 80 L. A smaller tank speeds up nitrate build-up and raises stress levels.

What water parameters does Ceylon Loach need?

Temperature 20–24 °C, pH 6–8, hardness 5–15 dGH. Stability matters more than exact values: sudden swings are harder on the fish than a small deviation from the ideal.

How long does Ceylon Loach live?

Around 4 years when kept properly. Lifespan depends directly on tank volume, water quality and a varied diet.

Is Ceylon Loach aggressive?

Temperament: aggressive / incompatible / unfriendly. Keep this in mind when choosing tank mates.

How many Ceylon Loach should be kept together?

Recommended setup: small group (3–4 individuals). Ignoring this is a common cause of stress and disease.

What does Ceylon Loach eat?

Diet type: sinking (any). Feed small portions that are finished within a couple of minutes — overfeeding does more harm than underfeeding.

What is the scientific name of Ceylon Loach?

The scientific name of the species is Schistura notostigma, family Nemacheilidae. It also appears in the literature as: Nemacheilus notostigma, Nemachilus notostigma, Noemacheilus notostigma.

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Other scientific names and conservation status

Other scientific names
Nemacheilus notostigma, Nemachilus notostigma, Noemacheilus notostigma
Categories
Loaches, Cold-water
Conservation status
Near threatenedNT