The Oscar Fish is an incredibly popular tropical freshwater fish that hails from the Amazon basin of South America. Their popularity is largely due to their intelligence levels, their playful behavior and their beautiful colourings.
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. Some Cichlids can become aggressive and the Oscar Fish is no exception so it’s recommended that they are kept in a tank of their own.
With that being said, aggression is not an Oscars default behaviour and outbursts are rare so feel free to take that recommendation with a pinch of salt.
Oscars 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. 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 a fully-grown size of around 10 – 12 inches.
Due to their sheer size, it’s important that you have more than enough tank for the Oscar fish to grow into and thrive in. Anything smaller than 55 gallon per fish will be a struggle and will put 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 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 clean water is absolutely essential to the health of your Oscars.
The perfect temperature for Oscar Fish is between 75 and 80 degrees Fahranheit (23 – 27 Celcius) 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 water filtration system as well as an aquarium heater with a built-in thermometer. 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 colour, a lack of appetite and a general unhappiness.
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
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.
What Do Oscar Fish Eat?
Now that you know what the ideal tank should look like for your Oscar Fish, it’s time to look at what 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.
In their natural habitat, Oscars will feed on a lot of small insects and crustaceans. Occasionally you can offer your Oscars live 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 is Tetra Cichlid Crisps
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 such as Hikari Tropical Wafers are a great way to add this fibrous plant matter into their diet without causing any bloating problems.
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
- 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 breeding Oscar fish is so difficult 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 the Tiger Oscar, Red Oscar, Albino Oscar, Yellow Oscar and the White Oscar. 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 colours 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 fertilise 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 will rarely get sick, it is not uncommon for them to contract several different diseases if you don’t look after them properly. 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 fishes 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 fishes 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 more fish to their space, it’s easy for the tank to get overcrowded and because Oscars are a territorial fish, that doesn’t usually bode well.
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. Plecs, Jack Dempsey’s and Arowanas are a few examples of fish we would recommend keeping with Oscars.
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 are a fascinating fish that are not only intelligent and fun to interact with but also beautiful to look at. If you are ready for the challenge of keeping this popular tropical fish, we hope this guide has given you some nuggets of information to make your job a little bit easier.