Green Oscar Fish – A Complete Guide

You may wonder about the appropriate fish type to introduce to your home aquarium. However, green Oscar is an excellent choice to consider. You will need the necessary information about your new friend.

Green Oscar fish is a product of variant cross-breeding carried out by many aquarists. They are either a product of combination from cross-breeding between two red Oscar, Albino Oscar, or tiger Oscar.

Having described the formation of green Oscars briefly, you should be intrigued to know more about the beautiful creature. Therefore, this article provides vital measures that will guide you in keeping your new friend.

Green Oscar Overview

Some people had doubted the existence of green Oscars. Although you will hardly find them in many fish stores, these beauties surely exist. They are products of several cross-breeds, whereas these result in their intricate and diverse colors and patterns.

Moreover, the primary color that appears on their body is a light green shade. But they sometimes have traces of yellow and dark green hues. Also, aquarists often hold green Oscars in high esteem, as they are rare to find.

Green Oscar Size

Often, green Oscars grow up to 10-12 inches. They reach a bodyweight of 3.2 pounds, whereas they can reach up to 14 inches in the wild.

Green Oscar Lifespan

All things being equal, green Oscars live up to 10-13 years. However, this lifespan can be greatly shortened by continuous unfavorable conditions, such as poor water conditions, poor eating habits, inadequate diet, and insufficient space.

Green Oscar Behavior

Green Oscar fish are known to be protective over their territorial space. Although they are not aggressive. But when they feel threatened in their habitat, they can be somewhat offensive to the predator. Moreover, green Oscars are schooling fish. That is, they love living in the same space with other tropical species. Each of them protects its area and dig the bottom of the tank in search of food. However, when it’s time to breed, they pair up.

 Make sure you put more females than males in an aquarium tank as many males against a female Oscar could be a threat to the female fish. The male Oscars will tend to fight for dominance or a female’s attention, which may harass the female Oscar.

Green Oscar display their beautiful appearance when you place them in a favorable condition. Especially the male gender. Usually, males have a more vibrant color. Also, you will enjoy watching your fish during the breeding process. The male will show off some display to attract the female fish.

Make sure you get close to your Oscar. By doing this, keeping them becomes more fun. One way to achieve this is by playing with your fingers on the tank surface. The movement of your finger will trigger them.

 Many people ask if Oscar fish can be sensitive enough to recognize its keeper’s voice. No doubt, they are highly intelligent. So, do not feel awkward when your fish respond to your voice. However, this happens when you have initiated a friendship “code” with your fish. Although it might take longer than expected, but you have to be patient with your new friend.

Green Oscar Food

To enhance the lifespan of your fish, make sure the tank water is clean, and serve a healthy eating routine. You should create diet diversity by providing a mixture from frozen foods, vegetables, pellets, fruits, and live foods.  However, pellets are essential food sources you shouldn’t neglect in your fish diet. As they are rich in vitamin C. whereas, vitamin C assists in bone formation and wound healing. Also, pellets contain essential proteins for bodybuilding and maintenance. Moreover, some foods that contain Astaxanthin, such as peas, will help improve the skin color of your fish.

You should add live foods to the green Oscar diet in small quantities. Although live foods stimulate growth, they are also vulnerable to parasite invasion. A large amount can cause diseases related to fat consumption, such as obesity. Live foods include beetles, prawns, shrimps, worms, plankton, crickets, and small fish. Also, Oscar’s food varies on size, depending on the fish’s developmental stage as it determines the size of the fish’s mouth.

You can also include feeder fish in their diet. But make sure it is safe for consumption. However, it’s best for fish owners to rear the feeder fish intended for serving Oscars themselves. If you are going to get feeder fish from pet stores, you can go for rosy red minnows or guppies as they are the least vulnerable to parasite among other feeder fish.

Commercial foods are sold in most pet stores. However, the most suitable processed foods for Oscars include beef heart, flakes, blood worms, wafers, pellets, and crisps. Generally, you should balance your Oscars diet by serving them both live and commercial foods.

Green Oscar Tank Size

Oscars grow at a fast rate. Especially when their owners care for them. Aside from their rapid growth rate, they also grow to a large size. Among tropical fishes, Oscar is one of the large species available. There is no specific tank size for Oscars, as it varies for dimensions and numbers. Although you should bear in mind that your fish tank size should meet its safety needs. Generally, a 10-gallon size is appropriate for one green Oscar. But you can keep a smaller fish in a smaller tank, like a 75-gallon size.

Green Oscar Tank Requirements  

Young Oscar fish grow at a fast pace. So, they are often large. Whereas, this influence their tank size. To enable them to move around freely, make sure you provide a tank big enough to accommodate the number of Oscars you will be keeping. At least, provide a 100-gallon size per fish.

Moreover, you should provide plenty of space for them. Avoid adding unnecessary decorations. Although live plants and rocks can serve as spots for hiding from predators, they can also hinder big fish movement. And they a territorial, inadequate space may cause them to fight each other. Make sure you don’t add any sharp object that could injure your fish fins while swimming.

Like other Oscars, green Oscar requires clean water. However, you can achieve this if you provide a filter and heater in the tank. A heater will help regulate and maintain the water temperature. And a filter will help clean up dirt or messy foods in the tank water. Green Oscars are tropical species that thrive best at 72-77°F and 6.5-7.2 PH. Also, maintain a constant temperature as much as possible. Changing your tank water often may cause shock to your fish. Also, make sure the water current isn’t too fast.

Green Oscar Tank Mates

To raise green Oscars in an aquarium tank, they are better kept per unit or at most a pair. However, if you decide to keep more species in the same tank with Oscar, avoid raising them with smaller species as green Oscars are predators that can feed on smaller fishes. Therefore, you will need to keep them with larger species such as Aroqanas, Large Plecostomus, Jack Dempsey’s, and Black Pacus. However, make sure the tank you are keeping them is large enough to accommodate all.

In most cases, you will need a minimum of 250 gallons to enhance their movement in the aquarium tank. Also, you should choose fish that have the same behavior as Oscar fish. As a more aggressive specie than Oscar could cause harm to a fish, and your Oscar can also harm a less peaceful specie.

Green Oscar Breeding

After 2-3 days of mating, female Oscars release up to 100 eggs in batches. Some aquarists even claim their Oscar can lay up to 1000 eggs within few days. However, only a few eggs survive or reach adulthood in the wild. When captured, green Oscars fry can reach adulthood.

Moreover, Oscars fry hatches within the period of 72 hours. However, it is safer to put the babies in a “nanny” tank until the mother is well enough to take care of them. It enhances the probability of the babies growing at a fast pace. However, you may keep the babies in the new tank, without returning them. But bear in mind that they will keep growing larger. When you observe there is an increase in size, make sure to increase the tank size. It allows them to move freely in the aquarium. Also, make sure you provide a large breeding tank of at least 100-gallons.

How to Differentiate Green Oscar Sexes

It’s a fact that green Oscars share similar traits; however, it’s much possible to differentiate male and female sex. In most cases, they both have the same body size and length. However, the male is a bit larger. Also, the female genital papillae, which is located in their anal opening region, is usually broad and blunt.

Mating Green Oscar Fish

Having said earlier that green Oscars prefer their territorial space. However, they pair up when they are close to mating. Also, their activities will help you determine if they are close to coupling or not. These include; chasing one another, and nipping at each other’s fin. Also, they prepare where to lay eggs by picking sand with the mouth and dropping it off.

If you are going to pick two Oscars selectively for breeding, you need to put both fish in another tank and observe if they are compatible. If they are not fit, you can return them to the community tank, and select another pair for mating. Moreover, if one of the couple you chose, is aggressive towards the other fish, you can be sure they do not fit each other. Therefore, do not force them together. Also, bear in mind that mating is usually more natural if not less than two years. Besides, it’s preferable to select green Oscars that have mated before. Because, Oscars that have undergone the spawning process, will naturally spawn every month.

Another option is to raise juvenile Oscars until they are mature enough to select their mate. However, you will need to be patient. As some juvenile Oscar may not be sexually active until the age of 14 months.

Green Oscar Diseases   

When some cavities appear on the Oscar fish head, it’s a symptom of the most common disease associated with them. And it is popularly called hole-in-the-head disease. This disease result from the deficiency of essential nutrients Oscars needs for healthy development. These nutrients include Phosphorus, vitamin C, calcium. Generally, vitamin C supports bone formation. Improper filtration system can also cause this disease. Moreover, unbalanced diets also contribute to the severity of this disease.

Generally, green Oscars are easy to raise. Bacteria, parasites, or fungal hardly infect them. Whereas, the significant disease they are likely vulnerable to, is the hole in the head. However, you can prevent this by following proper measures. You should treat them effectively if the symptoms are spotted at an early stage.

Moreover, make sure you quarantine any object or fish you are introducing into your tank. It helps to confirm if they haven’t been infected. Also, remove any sick fish and put them in a different tank.

 Green Oscar Facts

You may wonder why many aquarists find this fish intriguing. Here are some interesting facts you may want to know:

  • Ocelli – Like other Oscars, this fish possess an eyespot, sometimes referred to “ocelli,” located on their fins. Also, they appear as a round spot. Whereas, this is particularly noticeable among wild Oscars. However, many researchers claim that the eyespot is a protective mechanism. As it helps wade off predators. They confuse predators by appearing to be dead.
  • Floundering Fins – Unlike many fishes, Oscars have a high survivor rate of fin nipping. When you put them in the same tank with fin nippers like mollies, they are hardly affected, because of their floundering fins. Also, it prevents parasites from infecting Oscar’s fins.
  • Habitat’s Mate – In the wild, Oscars often coexist with piranhas. Although researchers claimed that piranhas are no threat to the life of Oscars, but they sometimes bite Oscars. However, ocelli helps manage this behavior.
  • Protective Attitude – Usually, Oscars are protective of whatever belongs to them. Sometimes, this can be a good trait. For example, parent Oscars being protective of their eggs. They nurture, clean, and keep them well, unlike piranhas that feed on their young immediately after birth. However, this is another challenge that occurs in the wild as piranhas may likely feed on Oscar eggs. When piranhas show this toward Oscars fry, they become aggressive and protect their babies.

Green Oscar FAQs

Some popular questions are related to Oscar fish. These questions include;

Where Does Green Oscars Live?

You will find many wild Oscars in streams and rivers. Usually, they prefer slow and freshwater habitat. Also, they target places with a muddy end or bottom. When captured, people keep them in an aquarium large enough to contain the size and number of fish.

Moreover, Oscars are native of South and Central America. Majorly, they reside in Amazon River Basin. You will likely see them in places like Columbia, Brazil, Ecuador, and Peru. However, due to the current interruption of their habitat, they also exist in Asia, Australia, and Florida.

What Vegetables Can I Feed My Green Oscar?

Oscars can eat a variety of vegetables, including spinach, cucumber, carrots, and peas. Moreover, they enhance the green color of fish – the reason why you should introduce vegetables in your green Oscar diet.

What Do Baby Green Oscar Eat?      

Baby Oscar’s food is not different from what adult Oscars eat. Young Oscars will still eat mealworms, bloodworms, daphnia, frozen foods, and brine shrimps. However, you should serve them in smaller quantity by grinding the foods into powdered or tiny form.

Can I Keep Oscar Fish as Pet?

Yes, you just made the right choice by deciding to keep them. Oscars are beautiful specie that you will enjoy watching whenever they display. However, make sure you purchase a captivated Oscar. Wild Oscars are vulnerable to diseases. Don’t just order for a fish online without visiting the fish store. You need to be sure of what you are getting before making a purchase.


Green Oscars are no different from other types of Oscar in terms of feeding, tank requirements, breeding method, and the general care level. However, their unique trait is seen in the appealing appearance and particular color variant. Although you may likely not find them in many stores, some fish keepers have a successful record of them.