A unique fast flowing river scape in a super shallow aquarium for hillstream loaches by James Taylor.
This is my homemade directional high flow super shallow aquarium (or river tank!). I have always liked to build random nature-inspired projects and a high flow rate river system is something I always wanted to do!
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This tank was homemade to get the size I wanted. Measuring 120cm (48") in length, but only 15cm (6") high it allows for fast water movement over the rocks. Two large cylinder shaped water pumps generate the high flow. Each one is connects to a hose that runs underneath the substrate and into a u-shaped outflow pipe.
Both pumps are adjustable so I can change the flow from one side to the other, or turned off completely for feeding etc. At full power the system has a water turnover of around 4000ltr/hr, a serious amount of water movement!
I cut filter foams to fit around the side intakes on the pumps, and another piece to fit across the back intakes. The foam is primarily to stop particles from entering the pumps. However, they have the bonus of acting like a ‘matten’ filter for beneficial bacteria. They are also easy to remove and clean when needed which is a bonus.
In addition, I also run a small Oase Filtosmart canister filter. The intake is at one end of the tank and the outflow at the opposite to maintain the linear flow pattern. This flow style is exactly what I aimed to create, although, it does present a few challenges.
Related article: Aquascaping with a shallow aquarium.
Challenges when building a riverscape
The first thing I had to do with this system was position the rocks in a way that directed the flow where I wanted. This involved a lot of trial and error and getting my hands wet. Put a rock in the wrong place and it is easy to direct that water straight out of the top of the tank and onto the floor. Similarly, too much flow lower down will blast the soft sand substrate up into the water column.
I also had to take into account the wellbeing of the fish. The tank's only inhabitants are hillstream loaches (Sewellia lineolata), which are perfect for the fast moving water. However, I wanted to ensure there were areas that are out of the current where they could rest if needed.
The next issue I came to was feeding the fish! These fish do need to graze on natural greenery to thrive. I have several planted aquariums, so promoting algae to grow was a little different as I normally try to battle with algae.
After leaving the lights on for a few weeks and turning the rocks green it was time to add the fish. This presented the next challenge – feeding supplemental food.
With the fast moving water, many foods simply end up in the filter foam instantly. Meaning that I either need to turn the system off to feed. Alternatively, I could find foods like repashy that could stand up to the current long enough for the fish to eat.
I had a similar issue with the plants. After planting, in my excitement, I forgot to check that I had turned the pumps down to minimum. A few seconds later every single plant was flying down the tank. After a few choice swear words and a replant things went much better!
Related article: The secret to setting up a better river aquarium.
Plant species for a river aquarium
I have experimented with several aquarium plant species. I have now settled on a few that seem to work well in this fast flowing environment.
In the bottom of the tank I have small Anubias species glued or firmly wedged into the rocks. I also tied Monosolenium tenerum to rocks with thread and this adds a real river look!
Further up in the flow I have Vallisneria spiralis 'Tiger'. This looks amazing with the water movement, and will grow the full length of the tank when given half the chance!
Lighting a super shallow aquarium
Another area of trial and error was getting the lighting right. Due to the very shallow water I found that most aquarium lights were just too powerful. While I wanted algae to grow, the excessive brightness may cause the fish to be skittish and create too much of an imbalance in the aquarium.
Instead, I opted for five small USB plant lights which I purchased from Amazon place all along the aquarium. These give enough light for the plants to stay healthy, and to grow enough algae to keep the fish happy.
Related article: How to keep hillstream and brook loaches in the aquarium
Do it again, but bigger!
All in all this has been a great experiment. The high flow allows you to see behaviours in the fish that I have just not seen in a standard tank. Once the hillstream loaches settled in they have been consistently breeding, which is great but does cause a problem. The tank's volume isn't that large so the breeding does mean I run the risk of the tank becoming overpopulated.
So, while it was something I always had in mind, the breeding of these fish has certainly sped it up. I now have plans to build a bigger version with enough water volume to house more fish and with pumps that can be adjusted without getting your hands wet!
For more photos and some videos of this head to James's instagram @nanolab.aq. You might even be one of the first to see the larger river scape.