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There can be numerous reasons an Oscars hides including because they are being bullied, they are weak due to illness or disease or they may hide because of external environmental factors like a loud TV or being too close to speakers.
Oscars are usually confident fish. They won’t always be the tank boss, but they can normally be seen out and about most of the time, swimming in the open areas of the tank, often minding their own business.
Over the last 30 years, countless Oscars have passed through my fish room. Tiger Oscars, Albino Oscars, and long-finned Oscars to name just a few. I currently have a trio of Lemon Oscars in a 180 gallon (680 liters) aquarium. It’s a tank full of color, movement, and personality.
Oscars Can Be Moody!
Oscars have bundles of personality, it’s part of their charm. The downside of all that personality is they can be stroppy.
If you’ve had your oscar for a while, and he is settled in the tank, maybe he is just in a mood with you. Give it a few hours and see if he snaps out of it. Maybe offer him his favorite food. A lump of frozen bloodworm always helps our Oscars get over whatever is bothering them.
When I place a new Oscar into a tank, they can sulk for a couple of days. They may well hide or lay on their sides on the bottom of the tank. This is just how Oscars are. They soon snap out of it once they get used to their new surroundings.
If your oscar has only been in his new tank for a day or two, don’t worry about him hiding. Give it 24 hours and offer him a treat like frozen bloodworms.
Is Your Oscar Being Bullied?
Although Oscars have a reputation for being aggressive, they really aren’t. Even a large oscar can be bullied, by a smaller, more aggressive fish. Sit in front of your tank for a short period and watch how your fish are interacting with one another.
If another fish is constantly pecking at your oscar, or forcing him into a corner, it may have a long-term effect on your Oscar’s physical and mental wellbeing.
If your oscar is being bullied, there are a few steps you can take to solve the problem. Firstly, do you have another tank you can move your oscar or the bully fish to? By taking one or other fish out of the tank, the bullying problem will be solved.
If you don’t have another tank available, try rearranging the current tank. Take all the rocks and decorations out and rearrange them. This simple trick can sometimes reset the hierarchy in the tank. Creating new or additional territories for those fish that desire them. Adding additional rocks or fake plants can help create line-of-sight blocks. If the fish can’t see each other, they are less likely to chase or bully one another.
I have had great success using these fake plants I picked up from Amazon
Is Your Oscar Unwell?
An oscar who is unwell may be inclined to hideaway. In the wild, a sick fish is vulnerable to attack. Try and observe your oscar to look for signs they are unwell. Do they have white spots on them or a white fungus growing? Can you see any signs of Hole in the Head?
Try offering your oscar his favorite food and see if you can get him to come out of hiding. If he eats readily, it’s a good sign he isn’t unwell.
If you can see signs of illness, take a look at our Oscar Health Guide to determine what is wrong and the best course of action. Modern fish treatments work wonders providing the correct treatment is selected and administered promptly.
Is Your Water Quality Good?
Water quality issues can sneak up on even the most experienced fish keeper. Water testing should become a natural part of fish keeping, but many of us don’t do it as often as we should.
The three main issues we test for are ammonia, nitrite, and nitrate. Ammonia is the most toxic to fish, followed by nitrite and then nitrate.
Oscars are very hardy fish, but an ammonia spike can cause their health to decline rapidly and can quickly kill your oscar. Use a good quality test kit (I use a Master Test kit from API like this one).
If the test kit shows one or more parameters are off, change a large portion of the tank water straight away and then retest. Continue over the next few days until the parameters are back under control.
One parameter we fish keepers often forget to check is the water temperature. Using a digital thermometer to measure the water temperature will let you know if your heater is playing up. Oscars like their water to be in the 75°F to 81°F (24°C to 27°C) range.
Oscars can tolerate temperatures slightly above or below, but not for long periods. If your heater has failed, replace it and monitor your oscar over the coming days. Hopefully, he’ll come out of hiding and be back to his normal self.
Is Your Tank In The Wrong Location?
It sounds silly, but if your tank is in an area where people are constantly walking past, or the TV is flashing brightly in front of your tank, it is possible the oscar just doesn’t feel comfortable.
Try putting a sheet over the front of the tank, but keep the ends uncovered so you can still see in. If after a day or so the oscar is out and about, he probably just doesn’t like the busy location his tank is in.
Try moving the tank to a quieter location, or rearranging the rocks and decorations so some parts of the front are covered. This will make your oscar feel more secure and will lead to him growing in confidence.
As he becomes used to his surroundings, slowly start to remove some of the rocks from the front of the tank, allowing him to get used to the additional traffic
Oscars are confident, out in the middle of the tank, kind of fish. If they are hiding for days on end it is a sure sign something is wrong. Work through each of the steps above and hopefully, your oscar will become that free-swimming bundle of personality we all love to see.