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November 15, 2013

The hillstream loaches or, as we like to call them, “the suckers” have gained popularity over the years. It seems that only a few are imported in on a regular basis, despite being easy to breed in captivity. From my understanding breeding them mainly requires an empty box filter placed in the center of the tank, providing some strong current and feeding them on a regular basis, and you will be knee deep in kids before you know it. If this is so easy to accomplish then you may be asking why we only get to see a few at a time? I believe that this is because importers haven’t taken the time to separate their catch. Often we see ‘mixed’ lots of different hillstream types arrive. Identifying each species is certainly no easy task. Even we can run into trouble making sure we received the right fish and have properly labeled them. This week we managed to bring in a couple of new types, and are able to provide some accurate information on them. I’d like to tell you more about a world hidden in the mountains of Asia…

The habitats of the hillstream loaches all consist of shallow, fast-flowing headwaters that are usually broken up by small pools or cascades. These waters are cooler in temperature, high in oxygen content, and are generally on the alkaline side (a pH above 7). Most of the fish will do alright with below neutral pH, but if you want to keep them long term their pH should be kept above 7. The streams usually are full of small pebbles or stones, and lack vegetation. Instead, large amounts of leaf litter and boulders are found. Hillstream loaches favor aquariums that possess similar environmental qualities if they are to be kept long term. Providing a strong current from either a canister filter or power-head will help with replicating such conditions. Unfortunately, this can make finding suitable tank-mates a bit challenging, since most tropical fish prefer warmer water. Two great options are fish in the Danio family or White Clouds, both of which will usually adapt to these conditions and make wonderful companions with their bottom dwelling friends.

Their diet can vary slightly between each species, ranging from grazing on benthic algae, to others preferring to feed on filamentous Cyanobacteria. When I found out the Pseudogastromyzon species liked to feed on Cyanobacteria I was a bit surprised. This is typically found in stagnant water, and most members found within the family live in waters that are more turbid—quite an interesting dietary preference. Outside of their natural environment all hillstream loaches will enjoy feedings of frozen or live baby brine, as well as Artemia and bloodworms. A good idea is to grow algae in a separate aquarium, either on pieces of PVC piping or rocks. By doing this, you can switch these pieces between the two tanks, translating into a constant food source for them. How brilliant!

Members of the family Pseudogastromyzon are not terribly aggressive, but males will claim and defend the best feeding spots in the aquarium. This is typical behavior of the Pseudogastromyzon laticeps “Red Tail Spotted Sucker”. Ideally, a tank around 30” in length is suitable to house a few males and their potential mates. An interesting note is that these hillstream loaches were collected alongside Rhinogobius zhoui “Scarlet Goby” from a stream on the Lianhua Mountain in southeastern China.

Pseudogastromyzon laticeps1

Pseudogastromyzon laticeps

Rhinogobius zhoui

From the Xi Jiang (West River) of southern China you can collect Erromyzon sinensis “Red Spotted Sucker Loach”. These landlocked hillstream loaches were once considered to be a member of the Protomyzon family of hillstream loaches from China (1980) until Kottelat found enough morphological differences between the two genera. He erected the genus Erromyzon in 2004 to cover the fish found on the mainland. The word erro translates into ‘to wander, or go the wrong way’, and myzon means ‘to suck’. The word sinensis means ‘from China’. Like other members found in the family these are best kept in small groups to really see their natural behavior.

Erromyzon sinensis

We have several variants from the island of Borneo in stock as well. From the eastern part of the island, Gastromyzon zebrinus “Eastern Borneo Sucker Loach” is found in the Sambas River in the Bengkayang regency of West Kalimantan. To the south, you’ll find Gastromyzon scitulus “Southern Borneo Sucker Loach” grazing on the rocks for their algae.

Gastromyzon zebrinus

Gastromyzon scitulus

From Vietnam we have Sewellia lineolata “Reticulated Hillstream Loach,” which didn’t establish itself in the aquarium trade until the mid-2000’s, but once it did it is easily one of the most popular aquarium pets when it comes to the hillstream types offered due to its striking appearance. Now, if you think the Reticulated Hillstream Loach is attractive, then Sewellia sp. “SEW01” “Spotted Hillstream Loach” will take your breath away (at least in my humble opinion). These hillstream loaches can be found living side by side S. lineolata in the Quang Nam province of Vietnam, but S. lineolata has a much broader range in Vietnam.

Sewellia lineolata

Sewellia sp SEW01

There you have it! A world quite literally stuck to rocks on a mountain. I’m sure as time goes by and more and more hobbyists get involved in hillstream loaches, we’ll see more and more of these imported in and eventually identified. If you can’t get enough fishy information from us then be sure to “like” our Facebook page,, and check out all our pics on Pinterest,

Until I write again!

Anthony Perry
Sales Manager