Scientific Name: Astronotus Ocellatus
Temperament: Semi Aggressive
Minimum Tank Size: 75 gallons for a single Oscar, 125 gallon or larger with tank mates
Average Size: 12-14"
Water Parameters: 75-80 F, 6.5-8 Ph
Origin: South America
The Oscar is a relatively large cichlid native to Peru, Ecuador, Colombia, Brazil, and French Guiana, and occurs in the Amazon River basin. It is a large bodied semi aggressive cichlid, known for its playful and personable behaviour and insatiable eating habits. Arguably one of the most popular cichlids and most common kept. The average size of an oscar in an aquarium will reach 12-14", although not uncommon to grow larger to around 16" but very rarely larger. A healthy well fed oscar in a proper sized aquarium should grow at around an inch per month for the first 10-12 months then will dramatically slow down, generally taking up to 3 years to reach full potential size.
Minimum Tank Requirements, Setup and Tank Mates:
For best growth and water quality it's advisable to have 75g for a single Oscar and 125g for 2 or other tank mates, helping with plenty of room to claim personal territory and dull aggression. Overall capacity is flexible since the footprint of the aquarium is what is important. Oscar needs a minimum footprint of 48x18 inches. The height is flexible since Oscars do not require large depths. Tank size is quite important and an often over looked factor in Oscar care, with a tank too small it becomes very difficult to maintain clean water and environment which will leave your fish susceptible to infections like hexamita (the parasite HITH is a symptom of) and deformed features.
Oscars can be very playful and personable and have very interesting behaviors. Some will play with toys such as ping pong balls and even ornaments in their tank, some will even let their owner pet them. The most common behavior that will stretch across almost every Oscar is its need to rearrange their environment. They will dig, rip up plants live or fake, try and move rocks and wood to suit the environment they want, so keep this in mind when choosing décor and scaping the tank. Another notable behavior trait in the aquarium is the way an Oscar will recognize its feeder more than other people. When you approach your tank your Oscar will act excited and sort of 'dance' in hopes to get food. When a stranger approaches your tank, it may instigate a sulking type behavior because it doesn't recognize the person with their face against the glass. Which brings me to another behavior point, the infamous Oscar sulk. Often during water changes, rescapes, or any other environmental or stressful situation, it is insanely common for an Oscar to almost pout like a child. They will move to a spot on the tank, often a corner, and just lay down and sulk. This can go on for days sometimes.
As with all cichlids each Oscar will have its own personality, some are placid and some can be complete assholes, so sometimes can be hit and miss when finding tank mates. Some of the more common choices are the Jack Dempsey, Texas cichlid, Gold Saum, Serverums, Black Convicts, or large Plecos and Silver Dollars. Like previously stated it will be hit and miss, some Oscars just anti social and want to live alone.
One of the largest misconceptions in keeping Oscars is that they are a strictly carnivorous predator fish. Because of this misconception, it's common that feeder fish are used in the aquarium hobby for Oscars, this is completely unnecessary as they offer little nutrition and often carry diseases that will be passed on to your fish. Also some fish like gold fish and minnows, which are commonly sold as feeder fish at your local fish store, carry an enzyme called thiaminase which causes a vitamin B deficiency, and can lead to liver disease. The reality of their diet, is that only about 10% of their natural diet is other fish. The Oscar is an insectivore, meaning it feeds mostly on insects worms and other invertebrates in the wild. They will also eat fallen fruit from overhanging trees that has landed on the surface, the bulging eyes and upturned mouth are both perfectly designed for grabbing prey and other food sources from the surface. Because of this natural fruit diet, Oscars have quite a high requirement for vitamin C.
A staple diet of high quality pellets containing vitamin C is recommended. To add variety and offer your Oscar some healthy treats, you can feed them insects and worms, shrimp tails, mussel meat, and also chopped up fruits like grapes, melon and banana.