Oscar Fish With Goldfish? Don’t Make This Mistake!

Nov 25, 2021

Oscar Fish With Goldfish

What a sight it would be to keep oscars and goldfish together, wouldn’t it? The tank would look nothing short of regal. But is it possible? Oscar fish with goldfish – does nature allow it? 

Let’s find out! 

Can I Keep Oscar Fish With Goldfish?

No, you cannot keep oscars with goldfish. I could bombard you with all the reasons they shouldn’t be housed together. But for starters, oscars will eat your goldfish 9 out of 10 times. 

Oscars don’t think of goldfish as anything other than their next meal. 

In fact, there are so many videos doing the rounds on the internet of oscars gobbling up goldfish effortlessly. 

Watch this video of a tiger oscar devouring 10 small goldfish! 

While oscars and goldfish aren’t meant to be together for most parts, there are some anomalies where they’ve happily coexisted. 

For example, a hobbyist on one fish forum shared that he has successfully raised oscar and goldfish together. Apparently, he raised them together since they were babies. 

And now, guess what? The oscar is super protective of the goldfish and wards off anyone who tries to come close to it. 

However, as I said, this is a super rare case. This is a pure deviation from what would happen normally. 

Below, I’ll discuss some reasons why you can’t really keep oscars with goldfish. 

Why Can’t You Keep Oscar Fish With Goldfish?

Keeping oscar fish with goldfish is a bad idea because the two need entirely different water temperatures to thrive. Also, oscars will try to devour anything they can fit in their mouth, and your goldfish will be no exception. 

Together, these fish will create an enormous amount of waste – I can only imagine! Thus, you will have to work your fingers to the bone to keep the tank clean. 

If you fail to maintain a clean environment, there’s a good chance that your oscar will contract the dreaded hole-in-the-head (HITH) disease, to which it’s super prone. 

Let’s have a quick look at these pointers. 

Oscars And Goldfish Need Different Water Temperatures 

Oscars are tropical fish that need warmer water. On the flip side, goldfish are coldwater fish. Therefore, the temperature for oscars should fall somewhere between 74-81°F (23-27°C), and the temperature for goldfish should clock in around 68°-74°F (20-23°).

I know that the requirements for both overlap at 74°F. But as you already know, it’s never a good idea to expose any fish to extreme environmental conditions, right?

It might not harm the fish immediately but quite seriously compromises their health and stunt their growth in the long run. 

I’ll briefly touch on what happens to fish when they’re kept at the wrong temperatures. 

An oscar exposed to cold water will have slowed metabolism and weakened immunity. So naturally, this makes the fish prone to a plethora of health conditions. 

On the other hand, goldfish exposed to warm water will become hyperactive and slowly suffocate due to lack of oxygen. 

Oscar Will Eat Your Goldfish 

As you saw in the video above, oscars can quickly devour goldfish without putting in any effort. In fact, it’s a common practice to feed them goldfish. But that comes with a whole set of risks that I’ll explain later.

Although omnivores, oscars lean pretty heavily towards a carnivore diet. They have pretty intense predatory instincts. 

The size factor also comes into play. Some goldfish grow voluptuously, but most kept in the aquarium never grow longer than 6 inches. 

However, an oscar’s average length is 12 inches. 

So, as long as they can fit goldfish into their mouths, they’ll definitely go for it. And even if the oscar fails to gobble the goldfish, needless to say, the latter will be left with life-impairing injuries. 

Let’s assume the goldfish makes it out alive. Still, the poor fish will lead an impoverished life under constant stress and fear of being eaten at any given moment. 

The oscar will relentlessly bully the goldfish, outcompete it for food and space, and lurk around waiting for the golden chance to snack on it. 

To put it bluntly, it’s simply not humane to keep these two species together. 

Together They Will Make A Big Mess

Saying oscars and goldfish together will make a big mess is a huge understatement. Goldfish are the messiest fish I know. And oscars give them a run for their money. 

On a forum, one hobbyist shared that his oscars excretes feces as long as a finger! 

If you ever keep these two fish together, it will cost you a significant amount of time, effort, and money to keep the tank pristine at all times. 

What’s worse is that a goldfish’s body produces a certain kind of slime that’s known to pollute the water quickly. 

On top of that, oscars are super susceptible to a disease called hole-in-the-head (HITH) that’s strongly linked to a dirty environment. If the tank’s nitrate levels aren’t maintained, it’s only a matter of time before your oscar develops small pits around its head. 

The Upkeep Will Be Costly 

The perfect tank size for a single oscar is 75 gallons. And the minimum recommended tank size for goldfish is 20 gallons. 

If you ever get around keeping oscars and goldfish together, they will require a big tank – I’m guessing 100 gallons and above. 

So, a bigger tank means bigger and more powerful equipment. Sometimes, you will even need two of each. 

Cleaning and maintaining a big tank will be another hassle. 

Keeping fish in smaller tanks translates to stunting their growth and shortening their lifespan. That’s because they won’t get enough exercise, will stress more often, and be more susceptible to illnesses.

All in all, it can be pretty costly and exhausting for you in the long run. So it’s definitely best to think long and hard before making any commitment like that. 

Recommended Readings!

Do Oscars Have Teeth? Related To Piranhas?

Can Oscars Live In Cold Water? How Long?

Are Oscar Fish Aggressive? Or Just Misunderstood?

How Long Does An Oscar Fish Live? 21 Years?

Why Is My Oscar Fish Lying On Its Side? 7 Possible Reasons Why!

Can Oscars Eat Goldfish?

Yes, oscars can eat goldfish. They’ll happily eat goldfish or any other fish they can fit in their mouth. So, if you can stomach the scene, you can occasionally give your fish goldfish. However, there are some caveats attached to it. 

Let’s discuss this below. 

3 Risks Of Feeding Oscars Goldfish 

Goldfish
Credits: Diego Martin (CC license)

  • Goldfish can carry deadly diseases 
  • Your oscar can choke
  • Your oscar will get finicky

Goldfish Can Carry Deadly Diseases 

Most goldfish we know and love are mass-produced in fish farms under unhygienic conditions. As a result, they are often prone to countless pathogens and parasites. 

And if your oscar consumes a sick goldfish, it will naturally also consume deadly parasites that can cause a health hazard. 

Your Oscar Can Choke 

An oscar choking on a goldfish can be unlikely, but we cannot completely rule it out. A live goldfish can easily be lodged in your oscar’s mouth, throat, or digestive tract. 

Most fish have evolved to have body shapes that will help them get stuck in the predator’s mouth as a defense mechanism. 

A couple of years back, one of my oscars died while trying to consume a catfish. I believe the spines on the fins choked the oscar. 

Your Oscar Will Get Finicky 

Who would want to eat bland pellets and flakes when you relish on tasty goldfish? Not your oscars for sure! 

If you routinely give your oscars goldfish or any other live food, they will slowly start deterring other readily available food options. 

And it doesn’t just spell trouble for your wallet but also oscar’s health. Most feeder goldfish aren’t bred in the right conditions or fed the proper diet. Therefore, they’re not as nutritious as we would like to think. 

Can You Raise Oscars And Goldfish Together From a Young Age? 

I came across some bloggers sharing that you can pull a few strings to keep oscars and goldfish together. They suggested tips like raising them together from the start. But I’ll tell you why it won’t work. 

Oscars grow big and fast. In the first year, they’ll at least grow over an inch every month. So, even if you raise oscars and goldfish since infancy, the oscar will quickly outgrow a goldfish and potentially eat it. 

However, if you are bent over backward to raise oscars and goldfish together, here are a few tips that can help you. 

But mind you, consume this information with a pinch of salt. We don’t really recommend raising these two species together. 

How To Keep Oscars And Goldfish Together?

To increase the chances of successfully raising oscars and goldfish together, first, set the temperature in the middle ground that’s acceptable for both parties. Also, make sure the tank is big, and there’s plenty of hiding space for goldfish. And last, feed the fish properly, so they don’t get hangry! 

Get A Bigger Tank 

Getting a bigger tank is indispensable. Goldfish are social and not too picky about what part they swim in. However, oscars are highly territorial. They claim territories and fiercely defend them. So, you’d want to make sure there’s no animosity regarding space. 

Also, since both parties are notorious for producing a sizable amount of waste, a small tank would get dirty a lot quicker.

The toxic build-up of compounds like ammonia and nitrite will happen too soon. Remember, the smaller the aquarium, the more temperamental it is. 

Balance The Temperature 

As I have already mentioned, oscars are tropical fish, and goldfish are coldwater fish.

Naturally, therefore, their temperature needs differ quite drastically. However, if you are really looking forward to raising them together, you can set the temperature in the middle range that’s not too cold for oscar or hot for goldfish. 

Even then, acclimatize the fish gradually using the drip acclimatization method so it can adapt better to the new environment. 

Include Plenty Of Hiding Places 

Oscars are aggressive fish. So, your goldfish will have to spend a lot of time hiding and hanging onto its dear life. Therefore, you must include plenty of hiding places in the tank. 

This way, your goldfish will have a safe haven to retreat to whenever it’s stressed or being chased by the oscar. 

However, note that oscars have a reputation for toppling and rearranging decors as they see fit. Therefore, you should go with relatively large decor items and anchor the plants securely so the oscar cannot move them. 

Also, place these decor items in such a way that it breaks the line of sight. For this, you can pile the rocks on top of each other. This helps to reduce violent encounters in the tank quite significantly. 

Feed The Fish Properly 

If you keep your oscars well-fed, chances are that they won’t go after your goldfish. A full oscar will not worry about his next meal and go after goldfish. 

Instead of giving one or two big meals a day, spread it out to three to four small meals. Each time, feed an amount they can consume within 30-40 seconds. This feeding style is known to curb aggression over resources. 

Also, while feeding, make sure to distribute the food across all regions so that your goldfish don’t have to directly compete with oscars for food. 

I have given you four tips on how to keep oscars and goldfish together, but I cannot really vouch for them. It can be a success, but it can go south pretty soon too. 

Therefore, before we sign off, I’ll tell you a bit about some suitable tankmates for oscars that you should choose over goldfish. 

5 Best Tankmates For Oscars 

jack dempsey cichlid
Credits: PINKE (Creative Commons license)

Ideally, a fish should qualify in two departments to be housed in the same tank as an oscar. First, they should be able to hold their own against the oscars. Second, they should be similarly-sized as oscars. 

In the list I’ve shared above, not all fish grow as big as oscars, but boy, are they fierce! 

All the fish listed above are assertive, aggressive. They can easily put up against an oscar if it’s ever being mean. 

Can Oscars Eat Goldfish Food?

Yes, oscars can eat goldfish food, but they really shouldn’t. This is because goldfish incline towards a herbivore diet, whereas oscars, like most American cichlids, need more protein and fat in their food, which they get from meat consumption. 

Therefore, goldfish and oscar food are often formulated differently to meet their unique nutritional needs.

So, even if your oscar can eat goldfish food, we strongly recommend sticking to species-specific food! 

Final Words: Oscar Fish With Goldfish 

No, oscars and goldfish don’t go together. They come from two entirely different continents and therefore need different water parameters to thrive.

Also, I’m sure you are acquainted with oscar’s aggression and carnivore instincts. Sooner or later, the goldfish will become a delicious snack for your oscar. 

Recommended Readings!

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Salvini Cichlid Care Guide | Diet, Habitat, Breeding, Accessories

rohit gurung author at urbanfishkeeping

About Rohit Gurung

My never-ending love and fascination with Aquascaping started when I received a red-eared turtle for my 10th birthday.

Apart from researching and writing, I spend hours gazing at my 3 turtles. And yeah, I bask alongside them too.