Hillstream loach week at Aquarium Glaser! Part 1: Introduction & Sewellia

23. March 2009

Currently we can offer a great number of varieties off hillstream loaches. That´s the reason for this week´s special. We want to show you how interesting and diverse these fishes are.

Sewellia lineolata

Systematically speaking, the hillstream loaches belong to the family Baltoridae. This means that they are close relatives of the river loaches (Nemacheilus, Schistura etc) which are also members of the Balitoridae. Hillstream loaches are adapted to live in fast flowing water. Their pectoral and ventral fins are formed like the spoiler of a car and have the very same function: the water that flows over the fish presses them down. So the fish can withstand the current without much loss of energy.

In some species this fin apparatus is so effective that it enables the fish to climb over water falls!

As they are relatives of the river loaches they feed on a great variety of small animals, but they do not eat algae! In the aquarium they will accept frozen food, live food and many will also take dried food. Among each other they are usually peaceful. Short huntings are the worst they have to face from congeneers. Other species become usually totally ignored.

The tank setup for hillstream loaches should be orientated on a brook. It should content stones and roots. Plants are of minor interest for the fishes. One should know that all hillstream loaches are very sensitive against nitrite.

Breeding hillstream loaches was successful in recent times. Since the first importation of the spectacular Sewellia lineolata aquaristis developed a great ambition to breed them. Females are larger and thicker. They spawn almost daily over a long period. Breeders offer clusters of pebbles with 2-4cm granualtion. The eggs disappear in these clusters and cannot be eaten by the always hungry parents. The gaps between the pebbles are also home for the fry until they are big enough to leave them without being in danger to end as food for the parents.

Sewellia sp. “Spotted”

Our journey through the world of hillstream loaches starts with Sewellia. We have in stock three species from Vietnam: Sewellia lineolata that can grow up to 6.5–7cm, an undescribed species called S. sp. „Spotted“ and for the first time ever S. breviventralis. The latter has been described in the year 2000. The scientists knew at the time only juvenile specimens. We can offer also adult specimens of about 6cm length. Many specimens show broad barres over the back, but the coloration varies a lot individually and there are also almost plain animals.

Sewellia breviventralis

Although S. breviventralis is known as an extremely rheophilous species they thrive very well in captivity. All three species of Sewellia should be kept at temperatures between 18 and 24°C. Higher temperatures over a long period lead to starving fishes. Their metabolism then needs more energy than the fish can feed. The remaining water conditions are of minor interest. Moderatly hard water with a neutral pH is perfect.

Sewellia breviventralis

For our customers: Sewellia lineolata has codenummer 455054, S. breviventralis 455043 and S. sp. „Spotted“ 455075 on our stocklist. Please note that we exclusively supply the wholesale market.

Text & photos: Frank Schäfer