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How big a tank is it? Yes single is fine but they are probably best kept in at least a pair if you want to see their neat behaviors. While they are a social fish, I think the general guideline that I have seen is that the bolivian ram should each have a territory that is about 8-10 inches square of your tanks footprint with lines of sight broken by decorations/plants especially if you have a mating pair. I had 5 in my 58 gallon and they were amazing to watch commune together but when a pair were hooking up they basically took over 3/4 of the tank and pushed the remaining fish to the side glass. If I were to do it again I would only put at most 3 in the 58 Gallon or 2 in a 30 gallon.
31 Gallon Hagen Waterhome with 2 x 20W T8 6700K Life Glo tubes, Fluval 205 canister filter, Aquaclear 200W and Marineland Stealth 150W heaters, Hydor Hydrokable 50W substrate heating cable with Hydrostat thermostat, Hydor Ario 2 Blue aeration night light. Compressed CO2. Very Heavily Planted.
58 Gallon Hagen Light-Glo/Waterhome with 2x40W T8, 2x Fluval 404/405 canisters filters, Ebo-Jager 250W Heater, Marineland Stealth Pro 300W heater. Compressed CO2. Moderately planted.