by Jennifer Phillips and Michael Daly
Oscars, or Astronotus ocellatus, are an interesting fish that have become fairly common to the household aquarium. They are omnivorous Cichlids that are native to the Amazon River Basin region of South America. They are readily available as pets and are more commonly known by the names Oscar Fish, Common Oscar, Tiger Oscar, Red Oscar, Red Tiger Oscar, Marbled Cichlid, Velvet Oscar, and Albino Oscar.
Oscars are available as pets in a variety of colors such as Red, Tiger, Albino and Lutino, which are not found in nature. Although Oscars are still usually fairly small at purchase time, sometimes only an inch long, owners must be prepared with a spacious tank to accommodate their large adult size. This growth is very fast, and you may see your 1 inch baby Oscar grow to an amazing 9 inches in the first year. Oscars can grow to be between 11 and 16 inches long when kept in good conditions where they can thrive. A clean, spacious tank and a healthy diet are both very important for promoting a large, healthy fish. Well kept Oscars typically live 8 to 12 years in captivity.
Oscars can be easily found at any pet store, including in some department store pet sections with fish. It’s important that you are careful about where you purchase your fish, no matter what type you are looking for, so that you aren’t purchasing an animal with disease. Look closely at the condition of the fish before making any purchases. Avoid purchasing fish from tanks that have fish with torn fins, white spots or gashes on their skin, cloudy eyes, or if you see a number of dead fish in the tanks.
Oscars are often appealing due to the way they interact with humans. They have been nicknamed the “River, or Water dog” because of the way they behave. They have a habit of shaking, or wagging, their heads and tails much like a dog. Oscars are considered one of the most intelligent tropical fish that are aware of and curious about the surroundings outside their tank. They respond to seeing humans visiting on the other side of the glass, and some people believe that Oscars can even recognize their owners. They will even often beg for food when they see you. Although Oscars aren’t as colorful as many aquarium fish, and are sometimes even considered ugly, they still seem to have a way of winning people over with their unusual behaviors.
It is important to be aware that Oscars are semi-aggressive Cichlids, which means care must be taken when introducing any other new fish. In addition to other Oscars, a small number of other semi-aggressive Cichlids, such as Severeum, FireMouth Cichlid, Blue Acara & Convicts can be added cautiously. A few other fish, such as Eartheaters (Jurupari) , Plecostomus, Leporinus, Clown Loach, Jade Eyed Cichlid, Syndontis Catfish, and even Silver Dollars, if added in small groups, can be fairly decent tank mates. Any new fish added to the tank may be seen like a tasty treat if it is too small. As a general rule of thumb, Oscars will eat anything that fits in their mouth, so keep this in mind when selecting any additional fish to bring home.
Oscars require a good bit of space, with a single Oscar requiring a minimum of a 55 gallon tank, although bigger is better when it comes to tank size. A pair should have at least 100 gallons, but would be kept comfortably in a 125 gallon tank. Keeping Oscars individually or in pairs is recommended, since you may run into territorial problems in groups of 3 or more if a mating pair forms. Since it is very difficult to determine the sex of an Oscar, you can not control what you’ll end up with. Overcrowding them can cause health problems and will make it very difficult to maintain water quality.
Water quality management is something every Oscar owner must take seriously and do some research on, considering that most health problems are caused by water quality issues. While all the details of understanding water quality and all the types of water filtration systems are beyond the scope of this article, there are some general guidelines that can help maintain a healthy environment for your Oscar. Since they are fairly messy fish, it’s very important to have sufficient filtration for whatever size of aquarium that you choose. The basic filters that come with aquarium kits are not sufficient to keep up with the waste that is produced by a fish as large as an Oscar. It is recommended that you use a filter that is rated for twice the amount of water that you are actually filtering to deal with the Oscars mess. For example, if you have a 55 gallon aquarium, you would purchase a filtration system that is rated for about 100 gallons or larger. Weekly replacement of about 10% to 15% of the water and substrate cleaning should be done to help remove harmful chemical buildups and debris from the water, and also to replenish minerals. The chemistry of the water for an Oscar should have a pH range of 6 to 8. There are kits available for testing this and other water chemistry levels, such as ammonia, nitrite, nitrates that may affect your fish. It’s also important to make sure your fish have enough oxygen available in the water. This can easily be accomplished with just the water filtration system if it has a strong enough water output to cause agitation at the waters surface. An aeration pump can also be added to help with oxygenation, which also removes carbon dioxide from the water.
Place the tank away from areas that may cause temperature fluctuations such as near doors, windows, and vents that may be drafty, or near any heaters. Also avoid setting up the tank in a location that receives direct sunlight, because this may cause temperature changes and will also promote excessive algae growth. Also make sure that the tank is placed on sturdy surface capable of holding the considerable weight of a large aquarium, preferably a stand designed specifically for holding aquariums of such a large size. You should also make sure that the aquarium is level before filling it to avoid broken seals and cracks.
Since Oscars can grow to be fairly large, and like to rearrange their surroundings, don’t put a great deal of effort into decorations. If you have to have decorations in your tank, choose larger, heavier decorations that are harder to move than lighter things such as plants, and that have no pointy or sharp edges that could injure an Oscar who is trying to redecorate. Plants are not likely to fare too well with an Oscar, as most owners will tell you that their Oscars will uproot any plants that they attempt to put in. Using a large rock or wood in your tank can act as not only a heavy decoration for your Oscar tank, but can also act as shelter or a place for the fish to hide when strategically placed.
Oscars prefer to live in a temperature range of 78-82°, so a quality heater, with a guard for protection, that allows you to specify the temperature is something you’ll need. You should also make sure that you have a thermometer to make sure that temperature is being maintained properly. Oscars do not need any specific lighting requirements, so the light that is included in a kit, or any other basic light setup that fits your aquarium size will be fine. You’ll also want a lid that you keep closed in between feedings to prevent your Oscar from jumping out of the tank. Gravel and sand are the most common substrates for the Oscar tank, and come in a wide variety of colors.
Feeding time is one of interesting aspects of keeping Oscars. They live for food, and show great enthusiasm at mealtime, sometimes even jumping out of the water to take food directly from your hand. There are a variety of types of quality foods available for feeding Oscars, but packaged foods such as pellets, flakes, freeze dried foods are safer and easier than live foods, making them the preferred choice for the main diet by many owners. Blood and earth worms, as well as other live foods can be given as supplements to their primary diet. However, extreme caution must be taken when feeding live foods, since the Oscar may injure himself when chasing particularly fast meals, on objects in the aquarium such as the glass heater, filter intakes, and sharp edges on decorations. Most experts do not recommend any type of feeder fish, because they lack nutrients and have a high risk of introducing disease. Only feed your Oscar as much as he can eat in 2 to 3 minutes, once each day, to avoid overfeeding which can not only negatively impact their health, but can also lead to water quality problems.
Oscars don’t have many health problems to deal with, but there are a few. Hole in the Head disease (HITH) is something that can affect Oscars who are not kept in healthy conditions, and actually causes holes to begin forming on their head. Maintaining clean water quality and feeding the Oscar a healthy diet is the way to prevent this disease, although medications are available to treat it if it does occur. Oscars can also get a parasitic infection, called White Spot or Ick, which can be easily treated with medication.
Oscars can be a unique addition to your household that are unlike any other fish you’ve kept in an aquarium. They can be some work when it comes to keeping their environment clean, but your effort will be rewarded as you enjoy this unusual pet fish. With the proper equipment and knowledge, you’ll be able to give your pet the best care and enjoy their company for years.