The Ultimate Oscar Fish Care Guide

The Oscar fish (or Oscar Cichlid) is an incredibly popular tropical freshwater fish that hails from the Amazon river basin of South America. Their popularity is largely due to their intelligence levels, their playful behavior, and their beautiful colorings.

There are lots of variations of the Oscar fish, including the Black Oscar, Albino Oscar, Red Oscar, Tiger Oscar, to name a few.

Oscar fish (also known as Velvet Cichlids) are not the easiest fish to care for, so we only recommend them to aquarists who have a bit of experience under their belts. Knowing how to care for Oscar fish properly will open up a new world of opportunities for you to keep other Cichlids in the future. They really are one of the most beautiful fish to keep if you know-how.

Some Cichlids can become aggressive and the Oscar fish is no exception so it’s recommended that they are kept in an aquarium free of tank mates.

With that being said, aggression is not an Oscar’s default behavior and outbursts are rare so feel free to take that recommendation with a pinch of salt.

How To Care For Oscar Fish

How Fast Do Oscars Grow?

Oscar fish grow astonishingly fast, so it’s important that you understand what you are getting yourself into when you pick them up from the pet store or a Cichlid breeder. It’s said that these popular freshwater fish can grow at a rate of 1 inch per month until they reach adulthood. If you don’t have a large enough tank (55 gallons+), then your Oscar fish’s health will be compromised and they will be at higher risk of disease and premature death.

Oscar fish babies are as small as any other tropical fish when they are young (1 to 2 inches) but under the right conditions, they can grow at a rate of 1 inch per month, to around 10 – 12 inches as a full-grown Oscar fish.

Oscar Fish Lifespan

An Oscar fish is a hardy fish and will live for a very long time if you maintain good quality water in your aquarium. In ideal conditions, an Oscar fish can live for up to 20 years. On average, Oscars will live between 10 and 20 years.

Oscar Fish Care 101: Tank Requirements

Due to their sheer size, it’s important that you have more than enough tank space for the Oscar fish to grow into and thrive in. An Oscar fish tank size should be no smaller than 55 gallons per fish to prevent putting any unnecessary stress on the fish.

Oscars are notoriously messy fish and require a lot more maintenance than most other species. Oscars produce a lot of waste so frequent water changes are a given necessity, but the smaller the tank that you house them in, the more frequently you will have to clean them and check the water parameters.

Oscar fish enjoy living in pairs or small groups. We would recommend keeping multiple Oscar fish (at least 2, or even 5 if you have the space).

Keeping three isn’t always a good idea as two of the fish could bond and dismiss the other one.

Oscars are sensitive to changes in water parameters and they are also susceptible to common tropical fish diseases such as ich, dropsy, fin rot, and tail rot.

We will discuss the most common Oscar fish diseases later in this guide but for now, just remember that good water quality is absolutely essential to the health of your Oscars.

Oscar Fish Water Parameters (Temperature and pH):

The best temperature for Oscar fish is between 75 and 80 degrees Fahrenheit (23 – 27°C) and they prefer a pH balance of between 6 and 8.

Oscars can tolerate a wide range of water hardness levels but we would recommend keeping it around 12dH – 15dH.

Oscars are very sensitive to changes in water temperature as well as increases in ammonia levels. Because of this, we would recommend a good quality filtration system as well as an aquarium heater with a built-in thermostat.

Not knowing the precise temperature and letting the ammonia levels spike is a surefire way to cause stress in the fish, leading to a loss of color, a lack of appetite, and general unhappiness and poor quality of life.

Make sure you have a good quality water test kit on hand to regularly test the water parameters. The one we use religiously that has never let us down is the API Freshwater Test Kit.

Do Oscar Fish Need Plants?

In terms of the tank setup and decorations, I wouldn’t worry too much about it. Oscars love to rearrange their environment themselves so just add a few plants, rocks, and ornaments and let them get to work playing interior designer.

Oscars are also a moody fish. They are unpredictable. One minute they could love the plants in their fish tank, the next minute they could be uprooting them and throwing them around the aquarium in a tantrum. For this reason, it’s important to choose plants that are hardy and won’t die as soon as they are touched. Floating plants are also a great way to keep the Oscar fish aquarium looking green without causing too many problems with your Oscars.

Oscar fish love these plants:

• Java Fern
• Salvinia Natans
• Java Moss

One thing to remember: make sure you choose plants that have similar water requirements. It’s no use having a plant that requires higher water temperature or hardier water. Think fish first, then plants after. There are hundreds of species of plants that can thrive in an Oscar tank, so there’s plenty to choose from.

What Do Oscar Fish Eat? (Oscar Fish Diet)

Now that you know what the ideal tank should look like for your Oscar fish, it’s time to look at what fish food you should be feeding them.

Oscars are very liberal when it comes to their diet. They will eat almost anything that you put inside their tank.

Because of this and also because of their size, it’s crucial that you understand their nutritional needs fully and it’s up to you to make sure that they are met. A balanced diet is always recommended.

What’s an Oscar Fish’s Diet In It’s Natural Environment?

In their natural habitat, Oscar fish eat a lot of small insects and crustaceans. Occasionally you can offer your Oscars live fish foods as well as feeder fish such as Goldfish or Rosy Red Minnows.

It’s worth noting, however, that feeder fish are not nutritionally adequate and usually contain too much fat if fed in large quantities.

To be on the safe side and to make sure that your Oscars are getting fed everything that they need, we would recommend feeding an equal amount of processed flake or pellet foods and live foods such as insects, shrimps, and worms.

The base food that we recommend for Oscar fish are the floating cichlid sticks by Tetra. They are the perfect size and cover the base nutritional requirements to keep your Oscar fish healthy.

Oscars also require a higher level of Vitamin C and plant matter which they would usually get offhand from the prey that they would eat in the wild.
Algae supplements are a great way to add this fibrous plant matter into their diet without causing any bloating problems (I love these ones from Amazon. The absolute best bang for your buck).
Just like their owners, Oscars love variety in their diets and will appreciate a consistent circulation of different types of foods. Here is a “shopping list” of suitable foods that we would recommend:

• Brine Shrimp
• Bloodworm
• Krill
• Cichlid Pellets/Flakes/Wafers
• Frozen Peas

Breeding Oscar Fish – Is It Possible?

Oscar fish breeding is definitely possible but it’s not the easiest of feats to accomplish. In terms of the difficulty level compared to other freshwater fish, they are undoubtedly up there as one of the hardest.

The reason why it is so difficult to breed Oscar fish is because they are very picky when it comes to choosing a mate. They also need to be “mature” enough to begin spawning which is usually around 16 months to 2 years of age.

The two options that you have are to purchase a mating pair that have already produced offspring in the past or to purchase a bunch of juveniles and allow them to grow up with each other and build a connection naturally.

The problem with the latter option is the fact that it can take a long time before the fish are ready to mate so if you are in any sort of a hurry, you are better off sticking with the first option of purchasing a pair that are already mating.

Which Oscar Fish Types Can I Successfully Breed?

There are many different types of Oscar fish in home aquariums all over the world, some natural and some not so natural.

It is possible to breed any combination of Oscar fish successfully as long as they will “connect” and establish a mutual liking of each other.

A few of the most common types of Oscar fish that you may want to consider breeding are Tiger Oscars, Red Oscars, Albino Oscars, Lemon Oscars, and the White Oscars.

Pink and purple varieties are not found naturally in the wild so we would recommend steering clear of those if you ever have the chance to purchase them.

Cross-breeding the different colors requires no additional information or steps in order to be successful. As long as the fish connect with each other, you are good to go.

Sexing Oscar Fish

Once you have decided to give breeding a go, it’s time to identify which of your fish are the males and which are the females. Unfortunately, identifying the sex of an Oscar fish is almost impossible unless you know exactly what to look for.

Oscar fish are known as “monomorphic” meaning they are exactly the same in terms of appearance regardless of their sex.

The only way to identify the sex of an Oscar fish is to take a closer look at their genitals.

Female Oscar fish have an “egg tube” that fully retracts inside of her when they are not in the process of breeding whereas a male Oscar will have a single sharp spike that he will use to fertilize the eggs.

Initiating The Breeding Session

Female Oscars will enter a breeding season when they sense that the rainy season is upon them. In-home aquariums, the water parameters tend to stay the same all year round so it’s not always easy for the fish to know when it’s time to breed.

To combat this, you will have to initiate the breeding season by creating your own “rainy season” when you want the fish to start breeding.

The first step is to do a large water change. 20 – 30% every couple of days will be sufficient.

One of the key indicators of the rainy season (besides from the presence of rain) is a noticeable drop in temperature. If you can lower the temperature of your aquarium by a few degrees, the fish will sense that the rainy season is starting and they will begin looking for a mate.

To simulate rainfall, simply use a watering can to sprinkle water on the top of the aquarium for 5 – 10 minutes a few times a day.

Alternatively, you can install a spray bar just above the water. This spraying of water will simulate rainfall without you having to do anything manually. Most canister filters will have a built-in spray bar.

Oscar Fish Common Diseases

Although healthy Oscars are less likely to get sick, it is not uncommon for them to contract several different diseases if you don’t take care of them properly. Follow the advice in our Oscar fish care guide and you won’t have many problems, but sometimes they are unavoidable. Nature has her ways of dealing us a dodgy hand from time to time.

The most common disease that Oscar fish fall ill to is a disease called “hole in the head” disease. It gets its name from the insurgence of cavities and holes that develop across the fish’s head and body.

Hole in the head disease is not particularly hard to treat, but the earlier that you spot any symptoms, the easier it will be.

It is typically caused by nutritional deficiencies in the fish’s diet. Follow the advice we offered in the diet section of this care guide and you shouldn’t have any problems.

If you are going to be feeding your fish any live feeder fish, always make sure that you quarantine them before adding them to your main tank. The biggest cause of diseases in tropical fish is the introduction of foreign bacterias from things that us owners carelessly put in their tank.

Suitable Tank Mates For Oscar Fish?

If you have got the space for an Oscar-only tank, that is what we would recommend. Oscars do better in pairs, or small groups but due to their size, they do need a huge amount of water per fish in order to thrive.
When you start adding other fish to their space, it’s easy for the tank to get overcrowded and because Oscars are territorial fish, that doesn’t usually bode well.
Oscar fish are not the friendliest of fish, even in their natural habitat, so you can imagine how they can be in a smaller aquarium with limited space. Oscars can get defensive and territorial, so it’s often advised to keep Oscars and only Oscars in your freshwater tank.
However, if you do want to keep other fish with your Oscars, make sure they are on the larger side and that they are passive/non-aggressive. A few Oscar fish tank mates that I have kept successfully include:

• Large Plecos
• Arowanas
• Convict Cichlids (or Firemouth Cichlids)
• Jack Dempseys

If the fish is small enough to fit in the Oscar’s mouth, chances are it will end up there. The same goes for invertebrates such as shrimps and snails. I wasn’t joking when I said they are notorious feeders. They certainly have an appetite!

Are Oscar Fish Intelligent?

You have probably heard from your aquarist friends, YouTube videos or other Oscar fish articles online that they are highly intelligent fish who can interact and “play” with their owners, but is it true?
Absolutely. They wouldn’t have earned themselves the nickname “water dogs” if that wasn’t the case. The way that Oscar fish will waggle their heads and fins when they see their owner walk into a room is heartwarming. Depending on how comfortable your Oscars are with you, they may even let you feed them with your hands.

Oscar Fish Care Made Easy

Oscar fish are fascinating fish that are not only intelligent and fun to interact with but also beautiful to look at. Here are our favorite recommended products for beginner fish keepers:

• NICREW Preset Aquarium Heater: Preset thermostat which automatically maintains water temperature at 78°F.
• API Freshwater Test Kit: Helps monitor water quality and prevent issues that can be harmful to Oscar fish.
• Tetra Cichlid Sticks: Protein-rich flakes that contribute to a nutritionally balanced diet.

If you are ready for the challenge of keeping this popular tropical fish, we hope this Oscar fish care guide has given you some nuggets of information to make your job a little bit easier.
Do you have any Oscar fish? Let us know your thoughts on them in the comment section below.