Edit Sewellia speciosa

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Name

Scientific name

Sewellia speciosa

Described by

Authority Roberts, Year 1998

Family

Gastromyzontidae

Common names

Not recorded

Photograph credits

All 14 credited

Summary

Sewellia speciosa is a hillstream loach that appears endemic to the Xe Kong river drainage in central Vietnam and southern Laos. It first b…

Size and aquarium

Maximum size

55mm, standard length

Aquarium size

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

Water

Water conditions

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, regions, rivers and lakes

Laos, Vietnam, Houai Sai, Mekong, Xe Kaman, Xe Kong, Xe Nam Noi, Xe Pian

Writing

Etymology

speciosa: from the Latin speciosus, meaning 'beautiful, showy'.

Distribution

S. speciosa appears endemic to the Xe Kong river drainage which rises in central Vietnam, flows across southern Laos and eventually enters eastern Cambodia whe…

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 cm 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 °C is recommende…

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…

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 described recovering fry that had been sucked into external canister filters in hill stream-style arrangements such as that described above (see 'Maintenance'), or discovery of small numbers surviving in mature community set-ups.

However subsequent experiments have shown that they can be bred in numbers in very simple quarters using groups of adult fish.

Perhaps the most important aspect in a controlled breeding attempt is provision of a suitable, mature substrate.

A large grade of rounded river gravel is best as the many nooks and crannies created allow eggs to develop within without being eaten by the adults and provides refuge for the fry until large enough to escape predation.

The organic detritus that tends to collect in this type of substrate also provides a food source for micro-organisms which in turn are eaten by fry.

Other décor can consist of some smooth, algae-covered rocks for the adults plus an air-powered, sponge-type filter to provide oxygenation and an additional grazing surface.

This type of filter has an added advantage in that eggs and fry won't be drawn into it.

Spawning can apparently be triggered by raising the temperature to 77-78.8°F/25-26° for a period before conducting a cool water change although in many cases simply performing the latter has proven enough.

Courtship is initiated by the male and involves fluttering displays and chasing of the female.

When a female appears receptive the behaviour of the male changes to include circling of his potential partner, mouthing of the dorsal surface and pushing of his head into her body, seemingly in an attempt to dislodge her into open water.

The act itself involves the pair rising into the water column with pectoral fins entwined before eggs and milt are released directly into the water flow, usually where the current is strongest.

Presumably this is an effective means of downstream dispersal in nature, allowing the fry to develop in quieter waters before migrating upstream to join the adults once approaching maturity.

In one experiment an adult pair of S. lineolata was provided with an open bowl filled with gravel and woollen mops within which the fish spawned suggesting that in nature spawning may be an opportunistic affair dependent on environmental conditions to an extent.

The incubation period for Sewellia eggs appears to be undocumented but once fry are spotted it's important to provide suitably-sized food items.

Infusoria is a good initial diet followed by Artemia nauplii, microworm, etc. once they're visibly foraging above the substrate.

The body shape of the fry is less laterally-compressed than in adults and they initially possess small barbels which reduce progressively as they mature.

The pectoral and pelvic fins are also relatively short to begin with meaning the young are unable to cling to surfaces in the same way as adults, instead spending all their time on or within the substrate.

The adults seem not to predate on the fry once they're around 5 mm0.2 in or so in length and they can be left together should you wish.

In community aquaria filtered by external units care should be taken when performing filter maintenance as fry can often be found inside.

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Notes

This species first became available in early 2010 and sometimes appears on trade lists under the vernacular names 'Laos sucker' or 'Laos Sakura sucker'. It's d…

References

12 on this profile

Name

Scientific name

Described by

Family

Common names

Photograph credits

Summary

Size and aquarium

Maximum size

Aquarium size

Water

Water conditions

Hardness

Conductivity

Behaviour

Temperament

Social needs

Community suitability

Where it lives

Countries, regions, rivers and lakes

Writing

Etymology

Distribution

Habitat

Aquarium size

Maintenance

Water conditions

Diet

Behaviour and compatibility

Sexual dimorphism

Reproduction

Notes

References

References