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Aquascaping & Decor


December 13, 2018 | By Oliver Lucanus

Did you know that the majority of freshwater aquarium fish often come from areas with fast flowing water? Despite the fact that many of them do just fine in relatively still, aged water aquariums, they typically do far better in greater spaces, with moderate or strong currents, and frequent water changes. Species such as loaches, Corydoras, most small barbs, tetras, livebearers and dwarf cichlids all prefer this type of atmosphere, however, many aquarium hobbyists fail to recognize this important point.

Today, I want to discuss how easily you can recreate a river environment or, more accurately, a small stream environment, with a 40 gallon aquarium, and how this unique set-up will allow you to see common aquarium fish in a much different and more natural way.

To build such an aquarium, I’m using a standard breeder 40 gallon aquarium with the measurements of 36″x18″x15″. Width is important here, because 3″ will be lost to the separating glass, making the final aquarium essentially 36″x15″x15″ – big enough to keep groups of common aquarium fish, but still small enough to find a space for it in your home.

If you’re not the handy type, you can always ask your local aquatic retailer or someone from the local aquarium society to help out. An experienced person can glue aquarium glass in 5 minutes or less.

You will need the following:

    1. One 200W heater, set to around 76F/27C;
    2. One canister filter, such as the FLUVAL 306;
    3. One strong LED or other light (remember, riverine environments usually get direct sunlight);
    4. One tube of aquarium-safe silicone;One 40 gallon aquarium (roughly 36″x18″x15″);
    5. One piece of black (smoked) glass from the glass shop with the sharp edges filed, 30″x15″;
    6. Two spare sponge blocks for a power filter, such as an Aquaclear 110;
    7. One 265L powerhead.

The sheet of glass should be in the back of the aquarium, leaving an equal space of 3″ on either side, with enough space behind to place the powerhead and cover the inflow side with the spare sponges. Which direction do you go? This is entirely up to you. Remember, the fish will mostly be facing into the current. If your aquarium is in the corner of the room, it will be more pleasing to see the fish swimming away from the corner than into it. So, if the left side of the tank is in the corner (as in my drawing), the powerhead should be facing to the right, thereby creating a current from right-to-left in the aquarium and allowing the fish to swim “into” the room.

For your substrate, use natural colours, ideally mixing sand and gravel together for a more natural look. Choose rocks that are flattened and have no sharp edges. In a river, there are no rocks with sharp edges as they are often flattened by the current. For plants, choose hardy species that are not easily uprooted, or those that can grow directly on the rocks. Some fishing string can be used to tie the plants down until they are attached. Suitable river plants are Bolbitis (African fern), Microsorium (java fern), Anubias, Vallisneria, Pogostemon, Cryptocoryne and many others.

What about wood? Well, this is not so common in fast moving rivers, so choose simple wood shapes that look like they could have become lodged among the rocks on their way downstream.

Current itself is a fascinating element to recreate in an aquarium, and is more interesting than you may think, so keep decor simple and to a minimum. Get outside and look at small streams in your area. What you see there is not so different from the tropics, and can give you a nice idea of how the environment should look.

To complete our river system, it’s important to remember that water changes much more frequently in a river. A 30% change every week should ensure you long lasting success.

Below are some examples of aquarium populations that would be geographically correct to further help you achieve a natural look and feel:


      • 10x Sewelia or Gastromyzon (stone sucker loaches)
      • 15x Tanichtys or Danio (white cloud mountain minnows, or Danios)
      • 15x Barbus (any smaller barb species)
      • 10x Botia or Leptobotia (smaller loaches)
      • 6x Nomorhamphus (half beak)


      • 6x Pelvicachromis (kribensis or related species)
      • 6x Synodontis nigriventris or other small Synodontis
      • 12x Phenacogrammus interrruptus or similar (Congo tetra)
      • 4x Steatocranus (buffalohead cichlid)
      • 3x Gnathonemus petersi (elephant nose) or Pantodon buchholzi (butterfly fish)


      • 15x Corydoras of any species
      • 5x Apistogramma or Dicrossus
      • 20x Hemigrammus (rummynose tetra)
      • 20x Moenkhausia sanctaefilomenae (red eye tetra)
      • 4x Hypancistrus, Baryancistrus or Ancistrus
      • 10x Otocinclus or Farlowella


      • 4x Ancistrus as algae eaters (there are actually some Ancistrus in southern Central America)
      • 6x Cryptoheros sajica or nanoluteus or Honduran convicts
      • 10x Poecilia velifera (sailfin molly)
      • 10x Xiphophorus (platys or swordtails)


15x Iriatherina werneri (threadin rainbow) or Pseudomugil
15x Melanotaenia spec. (rainbow fish, any species)
6x Hypseleotris compressus (empire gudgeon)
12x Stiphodon (slender algae goby)
15x Interesting snails from Southeast AsiaI hope this article will inspire some of you to try and create a river aquarium for yourselves. It really is simple, but does require a little time and effort. If you don’t want to glue the sheet of glass into your aquarium, you could also glue it directly to a piece of glass of the same length, around 6″ wide, creating a “T” shape. This “T” will act as a footing, and can hold the glass in place so it can be removed at any time.

Once your river tank is set up, I promise you’ll be fascinated by the new behaviour your tank life will exhibit. And don’t forget – healthy fish often reward “good” environmental conditions with frequent reproduction!


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