Edit Sewellia lineolata

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Name

Scientific name

Sewellia lineolata

Described by

Authority Valenciennes, Year 1846

Family

Gastromyzontidae

Summary

The tiger hillstream loach, Sewellia lineolata, is a gastromyzontid loach from fast-flowing headwaters in Vietnam and on the Mekong in Laos…

Size and aquarium

Maximum size

65mm, standard length

Tank size

Minimum length 75 cm, Minimum depth 30 cm, Water movement Very high: hillstream or torrent

Water

Temperature and pH

Temperature 20–24°C, pH 6–7.5

Hardness

1–10dGH

Conductivity

Not recorded

Behaviour

Temperament

Not recorded

Community suitability

Community-safe

Where it lives

Countries

Laos, Vietnam

Supporting text

Etymology

lineolata: from the Latin linea, meaning 'line', and -ola, the latter a suffix used to indicate small size.

Distribution

Native to Vietnam where it's known from the provinces of Thua Thien-Hue (Huong river drainage), Quang Nam (Thu Bon river), Quang Ngai (Tra Khuc and Ve rivers) …

Habitat

Restricted to shallow, fast-flowing, highly-oxygenated headwaters and tributaries characterised by stretches of riffles and runs broken up by pools or cascades…

Aquarium size

Minimum base dimensions of 75 ∗ 30 cm30 ∗ 12 in are recommended for general care. Smaller tanks can be used for breeding.

Maintenance

The water must be clean, well-oxygenated, and ideally turn over 15-20 times per hour so we suggest the use of an over-sized filter as a minimum requirement plu…

Water conditions

Temperature: Can tolerate higher temperatures provided its oxygen requirements are maintained but for general aquarium care a value of 20 – 24 °C68 – 75 °F is …

Diet

Much of the natural diet is composed of benthic algae plus associated micro-organisms although insect larvae are probably taken on an opportunistic basis. Home…

Behaviour and compatibility

In terms of behaviour Sewellia spp. are perhaps the most dominant of the 'sucker belly' group of loaches though they're not generally aggressive towards dissim…

Sexual dimorphism

The most obvious external characteristics are the shape of the head and body when viewed from above, with females having a comparatively broad body and a snout…

Reproduction

Sewellia spp. are arguably the easiest of all loach species to breed in aquaria and success has been achieved with several species. Initial reports mostly desc…

Notes

S. lineolata was first recorded by Diard over 150 years prior to its 'rediscovery' in the early-1990s. It became available to the aquarium trade in the mid-200…

S. lineolata was first recorded by Diard over 150 years prior to its 'rediscovery' in the early-1990s.

It became available to the aquarium trade in the mid-2000s and swiftly established itself as one of the more popular balitorids in the hobby due to its attractive body markings and ease of breeding.

It's also sold under the names 'reticulated hillstream loach', 'Vietnamese hillstream loach' and 'gold ring butterfly sucker'.

It's difficult to confuse with any other member of the genus as it possesses a striking series of 3-5 dark stripes on the body, and is further distinguishable by the following combination of characters: posterior portion of paired fins with 1-2 well-defined, concentric bands; origin of pelvic-fin below origin of dorsal-fin; origin of pectoral-fin posterior to corner of mouth; pelvic-fin reaching origin of anal-fin; small elevated patches of soft, fine tubercules on pectoral fins of males; tubercules on simple pectoral-fin ray not enlarged; absence of cavity around mouth and no skin-fold between oropectoral membrane and ventral surface of head; 38-49 lateral line scales.

In terms of morphology the most similar of the described species is S. speciosa but it has a distinctive spotted, vs. striped, colour pattern so in reality is easy to identify.

Prior to the mid-1990s S. lineolata was the only species in the genus but an upturn in surveys of freshwater fauna in Vietnam and Laos has resulted in the discovery of various new taxa, several of which remain undescribed.

The first addition was S. marmorata (Serov, 1996)[10] and this was followed by the description of a further four species in Roberts' 1998 revision.

He considered the larger-growing representatives with relatively short pelvic fins (S. elongata and S. diardi) to belong to his new subgenus Diardichthys.

Freyhof and Serov (2000) found S. marmorata and S. patella to exhibit a combination of characters applicable to both subgenera, however, thus Diardichthys is currently considered a synonym of Sewellia.

The genus is diagnosed by the following combination of characters as per Freyhof and Serov (2000): depressed head and body and compressed tail; greatest body depth at dorsal-fin origin; greatest body width at end of pectoral-fin base; entire ventral surface of paired fins, head and body forming an adhesive disc extending to end of pelvic fin; one simple and 19-26 branched pectoral-fin rays, one simple and 18-21 branched pelvic-fin rays; pectoral fin extending beyond pelvic-fin origin; last two pelvic-fin rays not exposed ventrally, but reflexed dorsally and adpressed to side of body, forming a pelvic valve together with a thick fleshy flap on posterior part of pelvic-fin base (where pelvic fin attaches to side of body); gill opening smaller than eye diameter, covered by a vertically oblique, biconvex membranous flap; gill opening entirely above pectoral-fin base; mouth very small, strongly curved; rostral cap continuous with upper lip; upper jaw overhanging lower jaw; two pairs of short rostral barbels and one pair of maxillary barbels; rostral barbels with medially expanded papilliferous bases, partly adjacent or overlying to cavities of ventral surface of head; these cavities not connected to each other; bases of two anterior barbels fused; rostral barbels connected laterally with a small skin-fold to head; maxillary barbel short and filamentous, with a few small papillae.

Sewellia spp. have specialised morphology adapted to life in fast-flowing water; the paired fins are orientated horizontally, head and body flattened and the last two pelvic-fin rays combine with a fleshy flap on the base of the fin to form a 'pelvic valve'.

These features form a powerful sucking cup which allows the fish to cling tightly to solid surfaces. The ability to swim in open water is greatly reduced and they instead 'crawl' their way over and under rocks.

The family Gastromyzontidae is currently considered valid as per Kottelat (2012).

It contains a number of genera which had formerly been included in several families and subfamilies, most recently Balitoridae, of which the most well-known in the aquarium hobby include Beaufortia, Formosania, Gastromyzon, Pseudogastromyzon, Hypergastromyzon, Liniparhomaloptera, Sewellia, and Vanmanenia.

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References

12 on this profile

Name

Scientific name

Described by

Family

Summary

Size and aquarium

Maximum size

Tank size

Water

Temperature and pH

Hardness

Conductivity

Behaviour

Temperament

Social needs

Community suitability

Where it lives

Countries

Supporting text

Etymology

Distribution

Habitat

Aquarium size

Maintenance

Water conditions

Diet

Behaviour and compatibility

Sexual dimorphism

Reproduction

Notes

References

References