Oscar fish is a very popular tropical fish and is a member of the cichlid fish family that originated in South America, in the waters of the Amazon. The Oscar fish is also known as the albino, red, and tiger Oscar and is found in a variety of colors and patterns like albino, olive-green, dark-gray, and brown. Generally, this fish grows large in size, reaching 12 to 14 inches (roughly 30 to 40 cm). Generally, a 55 gallon capacity aquarium or large size fish tank is essential for its proper growth and health. It weighs 1.5 kg (3 pounds) and feeds on pellets, freeze-dried fish foods, and other smaller fish that can fit into its mouth. The Oscar fish is one of the most-loved aquarium fish. Its popularity is due to the fact that it responds to its owner, just like a puppy. It plays and swims in the aquarium while its owner is around and it is believed that it has the ability to recognize its owner as well. It is also a brilliant actor and pretends to lie at the bottom of the tank/aquarium and in doing so, grabs the smaller fish that swim close to it. The diseases that affect the Oscar fish must be treated in a timely manner so that they do not become very serious or even fatal later on. Following is a list of some of these diseases. Fin Rot This disease causes the edges of the fins to turn white or the base of the fins to become ragged. In acute cases of fin rot, the fins may slowly become shorter over time. As this disease reaches an advanced stage, the area near the fins may develop bloody patches as the fins wither away. Fin rot is caused by a bacterial infection and can be treated with antibiotics. Septicemia Septicemia is a disease caused by a bacterial infection. It usually happens when an injury or wound is left open without properly treating it. In case of the Oscar fish, it can injure itself if it has a fight with the other fish in the aquarium. The water in the fish tank may get infected, so it is necessary that if a fish has injured itself, then the water should be changed immediately and treated with some antibiotics. Hole in The Head Disease (HITH) Various members of the cichlid family including the Oscar fish, are affected by the HITH disease that leads to small holes in the region near the head and around the facial area of the fish. There can be pitted areas along the lateral side of the fish and the holes can increase in size, looking like small craters. Though the exact cause of this disease is not known, it is believed that flagellated protozoans and bacteria cause its occurrence in Oscars. Velvet Disease Velvet disease is caused by the parasite Oodinium. These parasites first find a fish and then attach themselves to it using a flagellum. After that, they form rod pseudopodia that penetrate the skin and the soft tissues of the gills. The parasites feed on the nutrients inside the cells and after destroying the cells completely, they mature and rupture into dozens of cells. Each cell is released into the water tank to find a new host (each cell can thrive for 24 hours and if it does not find a host till then, it dies). This disease is very dangerous and can affect all the fish in the aquarium within a few days. Caring for this Fish Taking care of the Oscar fish is of utmost importance in order to keep it disease free. To ensure this, follow these steps.

• Once the aquarium is set up, wait for some days for the Oscar fish to settle, as they will be a bit uncomfortable for the first few days.
• Add only one or at most two fish at a time to the tank, as their biological filters take time to respond to the new changes and members of the tank.
• An Oscar fish must be quarantined before it is moved to the main aquarium. This will reduce the risk of infection to any other fish.
• This fish needs special treatment. Decorate your aquarium with lots of plants and small rocks and pebbles. Get it designed in such a way that the fish can hide. It loves to play and hide.
• Generally, this fish is a loner, but you can choose other fish that have a similar temperament as that of the Oscar. Neither a belligerent nor a passive Oscar is good for the other fish.
• Changing the water in the fish tank periodically is essential.
• Use a low-intensity light as the Oscar doesn't like bright lightning. You may use fluorescent light bulbs with ratings at 10,000K.
• Choose gravel that can't be swallowed by the fish.
• The air pumps and air stones must be placed so that they can oxygenate the water and disperse harmful chemicals into the air by stirring the surface of the water.

Oscar fish diseases can be controlled and treated by adopting proper methods of fish care. A vigilant fish owner will surely keep a check on their aquarium pets and treat them nicely.