Oscar fish are infamous for their aggression, which is hard to imagine since they swim so gracefully but they prove that looks can be deceiving. Those who are brave enough to keep them may initially be attracted by their appended and colors, but quickly come to appreciate their intelligence and social behaviors.
These are temperamental creatures that should only be looked after by experienced fish keepers. As omnivores, they are easy to feed, but it can be hard to find suitable tank mates. This is definitely a species worthy of a place in the home; Oscar fish complex behaviors will captivate you for hours.
|LIfespan:||Up to 20 Years|
|Size:||Up to 12 inches|
|Minimum Tank Size:||55 gallons|
|Tank Set-Up:||Freshwater: Rocks and Caves|
|Compatibility:||Large, Passive Fish|
Overview of Oscar Fish
Oscar fish is a species of cichlid, so it won’t surprise you that they are from the Cichlidae family. Most cichlids are from either Africa or South America, these are from the latter. They are native to Brazil, Columbia, Ecuador, French Guiana, and Peru. They can be found along the amazon river and its surrounding areas, which is one of the most biodiverse environments in the world.
Wild populations have also been found elsewhere (in places such as North America and China), though they have only spread to these areas through the fishkeeping industry. These fish are very popular for home aquariums, but they are not to be purchased without thought. They are infamous for their aggressive and territorial behavior which can make them difficult to handle. This is a species full of personality. A few different varieties have been bred which offer some different colors and patterns. Pick wisely because they can live up to 20 years if kept in good health.
Oscars are territorial, so adding them to the tank can be risky. They are not afraid to attack other fish and will do so if a fish encroaches on their territory. Mating and feeding times can also fuel their aggression.
Most of their time will be spent swimming in the mid-levels of the tank, though they will often head down to the substrate in search of food. You might see them uproot plants and decorations during this search, so everything in the aquarium should be secured down. The good news is that if that tank is set up correctly and you choose the right tank mates, their aggression can be controlled.
Types of Oscar Fish
Most varieties grow to be large, reaching up to 12 inches. They reach this size quickly in their lifetime, growing one inch a month until fully grown. They have a long oval body. The dorsal and anal fins extend along the body to the caudal fin, which forms a fan at the rear. You will find it difficult to sex this species as they are monomorphic, which means that both sexes have the same appearance. It takes a close look at the genitals to tell them apart.
Classically these cichlids are covered in an assortment of irregular black and orange splotches (tiger Oscars), but color may change over time. Many varieties have been created through selective breeding. Red and lemon Oscar fish have bodies that are almost completely solid red or yellow respectively. Their fins tend to be either black or white. Albinos are another popular choice, You can get albino varieties for lots of species, people are drawn to the bold white that covers the entire body.
The Perfect Tank for Oscar Fish Tank
Remember, fish have evolved to live in their natural regions, so you need to set your aquarium to replicate these natural conditions. The freshwater of South America is warm with a neutral pH, so it can not handle extremes in acidity or alkalinity. Water flow tends to be strong since most populations are found in rivers like the Amazon. While the sunlight would be strong, the water would not be crystal clear so some of the intensity is lost as the light penetrates the water.
At the bottom of the river would be a soft substrate with rock, debris, and vegetation scattered around on top. It is fairly easy to recreate these conditions in your tank.
What Size Aquarium Do Oscars Need?
Oscars will need a fairly large aquarium, 55 gallons or large is ideal. A smaller tank will cause them stress which will make them ill or more aggressive.
How Many Can be Kept Per Gallon?
Their size and need for territory mean each fish needs lots of space. Try 55 gallons for the first Oscar, then 20-30 gallons more for each additional fish.
At the base of the tank should be a layer of the soft substrate. The softest substrates are fine-grained, so the sand would be ideal. Oscars like to dig so a coarse substrate would scratch them. The most natural look would be to place rocks and bogwood around the tank, but you are free to choose any decorations. Make a couple of caves for each fish so that have somewhere to hideaway within their territory. Also, remember to firmly fix the decorations in place.
This species will dig around objects when looking for food which can dislodge them. Live plants are unlikely to be eaten, but they are still not safe. Just like decorations, plants may be uprooted while they dig through the substrate. Use hardy plants so they can survive the trauma. Floating plants should be safe from damage, a good option is a hornwort. Ideal water conditions are in the range of 74-81 oF, 6-8 pH, and 5-20 KH.
You do not need any special equipment to keep the water healthy, just a filter to clean it and a heater to maintain the ideal temperature range. Most aquarium lights are suitable too. Attach equipment firmly to the tank or they will suffer at the hands or fins of Oscar’s digging. Keep the lid on because these fish are powerful and may jump, or force other fish to jump. While they like strong currents in the wild, the filter outlet should create a strong current, so you should not need a water/air pump.
Oscar Fish Tank Mates
This fish is not the best at making friends. In South America, they live in some of the most diverse areas of the world, so they are used to lots of other fish. However, this is not the same in a tank because there is much less room, so tension rise. An Oscar fish-only tank is probably the best idea if you want these cichlids. If you are looking to turn your tank into a community then you will need to choose some large, passive fish that will stay out of the way while also being able to defend themselves.
Its aggressive nature can be cause tank mates to live in fear, so choose passive fish. A few good examples include Arowanas, Bichirs, Convict Cichlids, Firemouth Cichlids, Green Terrors, Jack Dempseys, Jaguar Cichlids, sailfin Plecos, Severum Cichlids, and Silver Dollars. As you can see, fellow cichlids are the most common tank mates since they can usually hold their own against an Oscar.
Any small fish you add will quickly disappear from the tank. This will be the same for shrimp and snail too.
What to feed Oscar fish
Whilst it can be difficult to find suitable tank mates for Oscar, providing a healthy diet is not. They are omnivores and will eat pretty, much anything you give them. In the wild, they would eat small fish, larvae, and small pieces of plant debris. Small insects and crustaceans would make up the largest part of their diet.
In an aquarium, the simplest option is to use store-bought flake/pellet foods. These have been designed to contain all nutrition your fish need, you can even buy some specifically for cichlids. Other options include live/frozen foods. These include bloodworms, brine shrimp, and daphnia. Live foods encourage Oscar to catch their food which brings out their natural hunting instincts. If you have some spare green vegetables around your kitchen then you can chop them up and put them in the tank. Or you can use them to make your own homemade fish foods.
Though they might nibble at plants, this won’t be a large part of their diet if you are feeding them enough of their foods. The best diet will be a mixture of different food types to provide a range of nutrients that your fish will need to stay healthy. Feed them a couple of times a day, in amounts that they can completely finish in a couple of minutes. Watch out for aggression as these cichlids get excited around food.
How to Care For Oscar Fish
Oscars require more care than most other species. Their size and large appetite mean that they produce a lot of mess. This makes cleaning the tank very important, or conditions will deteriorate quickly. Perform water changes at least once a week, ideally twice.
These cichlids are hardier than most fish, so they do not get sick often, but they can get ill just like all species. A common problem for these fish is “hole in the head” disease. This is where cavities and holes begin to form. This could be a sign that they are not getting enough nutrients in their food. it is worth changing their diet if you see signs of this disease.