Oscar fish are popular tropical freshwater aquarium fish among aquarists, featuring red or orange spots on the body. Plus, They are greedy and large, hence look clumsy. But they are sharp and active swimmers. So, if you’re ready to dive deeper into the aquatic world of Oscar fish and learn more about them, then let’s begin.
Oscar fish distribution
Oscar fish are native to South America, and you can find the fish in the Amazon River basin. Besides, Oscar fish are middle dwellers. They prefer slow-moving waters. Before getting into deeper learning about them, let’s take a quick look at basic information about Oscar fish.
| Family | Cichlidae | Ideal water temperature | 75-80℉ /23-27℃ |
| Common names | Oscar /Tiger Oscar/Velvet cichlid /Marble cichlid | pH level | 6-8 |
| Diet | Omnivore | Ammonia level | 0 ppm |
| Care Level | Moderate | Nitrite level | 0 ppm |
| Minimum tank size | 55 gallons | Nitrate level | Less than 20 ppm |
Are oscar fish aggressive
Oscar fish are aggressive and territorial. They will attack fish that pose threats and stress to them, while they will also defend their territory. Essentially, providing adequate room and hiding places is vital. Aside from that, you can decrease aggression by maintaining the living environment in great conditions.
How big do Oscar fish get
Oscar fish grow fast and large. What’s the Oscar fish size? Commonly, they can reach 12–18 inches with a weight of up to 3.5 lb (1.6 kg). You can help Oscar fish grow fast by providing a comfortable environment, plenty of space, and a diet rich in nutrition.
How long do Oscar fish live
Actually, the Oscar fish lifespan depends on owners’ maintenance. Generally, Oscar fish in captivity can live 8–12 years. However, they can live up to 20 years in the case of proper maintenance. By the way, keeping a great living environment and feeding balanced nutritious food is beneficial to extend the lifespan of Oscar fish.
What size tank for Oscar fish
The minimum tank size for Oscar fish
Oscar fish are hardy and can tolerate a wide range of water temperatures. Commonly, the minimum tank size for Oscar fish should be 55 gallons. Next, we will list the minimum tank size for some specific Oscar fish.
| Oscar fish | The minimum tank size |
| Tiger oscar fish | 55 gallons |
| Blue oscar fish | 65–75 gallons |
| Lemon oscar fish | 100 gallons |
| Albino oscar fish | 55–75 gallons |
| Black oscar fish | 65–75 gallons |
Oscar fish tank setup
(1)Add substrate? Yes or No?
Oscar fish consume a lot of food and produce a large amount of fish feces. Consequently, it is not recommended to add aquarium substrate in Oscar fish tanks. Because the fish feces will accumulate in the substrate, which poses risks of poor water quality. As a result, a fish tank without substrate is suitable for keeping Oscar fish.
(2)Oscar fish tank setup and decorations
As we have mentioned above, it is better to provide adequate hiding places. Hence, you can add rocks, stones, caves, wood, or other aquarium ornaments. Then, Oscar fish can hide in the face of stress or threats.
(3)How many Oscar fish are in a tank?
Besides that, Oscar fish are fond of living in pairs or small groups. Accordingly, it is feasible to keep 2 or 5 Oscar fish in the same tank as long as there is enough space.
What do Oscar fish eat
Oscar fish are guttler. They are omnivorous, but strictly demand vitamin C. Facing vitamin C deficiency, Oscar fish would suffer health problems. Then what to feed Oscar fish? The available food includes small live fish, shrimp, insects, worms, pellets, fresh and frozen foods, fruits, nuts, vegetables, etc.
Furthermore, you can feed small Oscar fish 2–3 times per day. Adult Oscar fish can be provided once each day or once every two days. Just determine the feeding frequency according to the status of your Oscar fish. But, no matter how often you feed, you should make sure the fish finish eating within 2–3 minutes.
Aside from that, take the albino Oscar fish as an example. They are omnivores. You can feed plant-based or meaty foods. Earthworms, bloodworms, brine shrimp, feeder fish, or other live, freeze-dried, and frozen foods are great options. Foods rich in protein can be fed regularly. Sometimes, you can also feed some vegetables, like cucumbers.
Determining the sex of Oscar fish
How to differentiate male and female Oscar fish? Generally, you can recognize them from size, body color, dorsal fin, anal fin, plus spots and strips.
As for male Oscar fish, their dorsal fins and anal fins are more extended and sharper than that of females, while males possess more brilliant spots and strips. Female Oscar fish, are larger and stouter than males. Featuring smaller anal fins, female Oscar fish have less bright body color, compared with male ones. Commonly, you can determine the sex of Oscar fish easily after the fish gets sexual maturity, usually 12–18 months after birth.
The final truth of oscar fish
Until now, do you have a deeper understanding of Oscar fish? This segment will cover more facts about Oscar fish.
Actually, Oscar fish need a sunbath. Otherwise, their body color will lessen. In general, keeping 2-3 hours sun bath each day helps to enhance fish’s body color.
Moreover, Oscar fish are aggressive. They would kill other Oscar fish sometimes or even eat small oscars. However, they would protect other fish in the case of a long time accompanied. Plus, Oscar fish are the most affectionate tropical fish. They can recognize their owners.
Additionally, Oscar fish can change their color rapidly. The colors of juvenile oscars are different from that of adult oscars. Featuring white and orange wavy bands on the body, juvenile oscars also have spots on the head.