Here is a part of an article I read that you might find helpful:
The Asian Riverbed Aquarium (120-200 liter)
This set up is very nice if you are willing to install a fairly strong current in your aquarium. It will mimic a South-East Asian riverbed biotope and should therefore ideally be heavily planted. Keeping a planted aquarium is actually easier than keeping a non-planted one since the plants will remove waste products from the water and help you keep the levels of oxygen up. Ask your local fish store for sturdy plant species that will thrive under normal
] and require no additional carbon dioxide or fertilizers. This Asia Riverbed setup is inhabited by 15 Zebra Danios, 10 Tiger barbs, 4 Tinfoil barbs and 1 Red Tail Shark. The Red Tail Shark is not a true shark; it is a shark minnow that lives in freshwater only.
The Gourami Aquarium (120-200 liters)
The Gourami Tank is a nice setup if you are a beginner aquarist with a 120-200 liter aquarium. The base of the aquarium will be two different Gourami species: the Pearl Gourami and the Dwarf Gourami. Combining two males and four females from each species (i.e. 12 Gouramis in total) will provide you with a good sex ratio. Two male and two female specimens of the Friendly Betta will add activity to the lower range of the aquarium, while a Bristlenose catfish (one of the Ancistrus spp.) will help you keep algae under control. Last but not least, add a school of six inexpensive Corydoras cat fish. They will add activity to the bottom as well as help you keep the aquarium clean. Never get less than six Corydoras since this is a schooling species.
The Malawi Tank (120-200 liters)
Many beginner aquarists automatically choose tetras and swordtails since this is what shop recommended them, but the world is filled with suitable beginner species and there is no need to go for the species that “everyone else” gets. Even as a beginner, a devoted aquarist can for instance successfully keep a Lake Malawi aquarium with colorful, albeit somewhat aggressive, cichlids. With a 120-200 liter aquarium, you will have room for quite a lot of medium-sized cichlids. Keeping the aquarium well-stocked will actually reduce aggression, so do not attempt this setup unless you are prepared to purchase all the fishes at once. The genus Pseudotropheus contains several suitable species and you can for instance pick six
Pseudotropheus estherae and six
Pseudotropheus socolofi. Add six more fish from the species
Labeotropheus trewavasae and finish by purchasing two Cuckoo catfish. These fishes hail from the rocky shores of Lake Malawi and the aquarium should therefore be aquascaped using lots of rocks. You can try adding plants if you want to, but they will most likely be destroyed.
