Tank Size: Tank size should be no less than 55 US gallon (208 liter) for one Oscar alone. Each additional Oscar increases the tank size by 25 US gallon (94 liter). The dimensions of the tank also come into play. Length is important because a mature Oscar needs swimming room. We recommend that the length of the tank be no less than 48" (121cm). The depth of the tank, from front to back, should be no less that 12" (30cm) to give a mature Oscar room to turn. Keeping all this in mind the ideal setup for one Oscar would be a 75gal (284 liter) tank which measures 48"W 18"D 21"H (121cm 45cm 53cm)
Filtration: The number of gallons or liters per hour is the important thing here but this depends of the type of filtration you choose. If you choose HOB (hang on back) filters you want to have a turnover of ten times the volume of the tank. With canister filters your shooting for five times the volume. With a combination of the two your looking for seven and a half times the tank volume. So for a 55gal tank with HOB filters we need 550gph. With canister filters we need 275gph. With a combination of both we need 413gph.
Additional Accessories you will need: Tank covers or lids are important because some Oscars like to jump. Aquarium heater large enough for the tank size. Two heaters are a good idea just in case one stops working. Aquarium thermometer in order to monitor temperature. Aquarium gravel or sand though this is not required. A basic water testing kit which will test for ammonia, nitrite, nitrate and ph.
Ideal Set Up:
- 75 gallon Aquarium
- HOB filter/s with a flow of at least 750gph
- Canister filter/s with a flow of at least 375gph
- A combination of both with a flow of at least 560gph
- Appropriate size aquarium hood with light
- Aquarium Heater (probably two to maintain proper temps)
- Aquarium Thermometer
- Aquarium gravel or sand
- Basic water testing kit for ammonia, nitrite, nitrate and ph
Once you have all your supplies your ready to begin. First and most important is that you have a stand or table on which to place your new fishy's home. Be sure it is sturdy enough to support the weight of the aquarium full of water and that it is near electrical outlets. Before you add anything to your aquarium, rinse it thoroughly with warm water. Never use any type of soap or detergent anywhere near your aquarium or accessories. It is very toxic to your fish and can kill them. Once you have rinsed and set your aquarium where it will be placed, fill it about 1/3 full of water.
Before adding your gravel, you will need to rinse it well to remove dust particles. You can do this by putting the gravel in a clean bucket and adding water. With your hand lift and swirl the gravel, you will see the water get cloudy. Pour cloudy water out and add new water to the bucket and repeat process until the water no longer clouds upon swirling. Once your gravel is rinsed, you can add it to your tank. Pour the gravel in to the tank gradually, taking care not to crack or damage the glass.
Put in your aquarium heater. Be warned Oscars have been known to attack, damage or crack there heaters. Try to place it somewhere you can put a tall plant in front of it to disguise it a bit. Place your thermometer on the inner side of the front glass. The filter/s are very important in your Oscar tank. It/they remove the large amount of waste Oscars are famous for and help to maintain water clarity in your tank. They provide chemical, biological and mechanical filtration functions that are essential to your tank. Rinse any filter material before putting it in the filter. Fill your tank to the inner lip and put your hood and light on. Your done all except for waiting (which is the hardest part), you need to cycle your tank before adding any fish. For information on how to do this see the Nitrification Cycle Simplified FAQ.