Why Is My Oscar Fish Laying On Its Side? {Is It Dying?}

Oscar fish lay on their side sometimes, but is it a cause for concern?

It looks like they’re dying, but are they really sick or dying?

In this article, we’ll try to calm any fears or concerns by discussing the reasons why oscar fish lay on their side.

Why Is My Oscar Fish Laying On Its Side?

Oscar fish lay on their side to take a break from anything that is concerning them. Stress or submission from external factors in their tank may cause oscar fish to lay on their side and chill out for a bit. This is not a serious concern 90% of the time.

As a pessimist, it’s easy to focus on the other 10% when laying on their side is a sign that something is seriously wrong. Maybe your oscar fish is sick or dying, but let’s stay objective first.

Is It Common For Oscar Fish To Lay On Their Side?

Yes and no. Oscar fish display unique personalities that separate themselves from each other. Much like humans, they display their temperament in passive or active ways. Some may become erratic or active. Other may need a timeout and lay out for a bit.

Would you rather have an oscar fish that flares its gills, opens its mouth wide and darts at your finger or tankmates? The alternative of seeing your oscar fish laying on its side, then resume their daily actions is preferred over aggression.

Do Oscar Lay On Their Side As a Sign of Submission?

Absolutely. This is one of the reasons why oscar fish lay on their side. They start to realize that they can’t run the show all the time. There could be other fish who are also defending their space in the tank as well.

Sometimes the oscar fish realizes it’s a lost cause trying to be territorial all the time. They have tried biting or chasing, but it may not have worked. Our hand or their tankmates may continue on with daily routines that invade their space.

Laying on their side at the bottom of the tank could mean that they are submitting to the pressures of not being in control all the time. They realize they can’t always win and it’s time for a break.

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How Can I Tell If Laying On Its Side Means My Oscar Fish Is Dying?

There’s a difference between sulking, submitting, needing a break and actually being ill or dying. If the oscar fish resumes swimming after short breaks, all is well. If they remain at the bottom of the tank and laying on their side for too long, then it’s time to observe more carefully.

  1. Longer periods of laying on their side
  2. Small holes in their head
  3. White spots
  4. Fin Rot
  5. Slow Breathing
  6. Flukes on gills
  7. Incorrect water parameters
  8. Cloudy eyes
  9. Not adjusting to new tank
  10. Aggressive tankmates
  11. Lack of appetite
  12. High ammonia levels
  13. Tank is too cold
  14. Toxic nitrogen compounds
  15. Not enough water changes

As you can see, the list is long, but this is our job as fishkeepers. We watch, observe and adjust our aquarium ecosystem when we notice that something is off.

Look closely at your oscar fish to notice external problems or abnormalities. See if they are acting slower than usual or not eating as much. Look for long stringy poop that is abnormal and may mean that parasites have infected your oscar fish.

It’s a process of elimination by referring to this list and seeing if there are any other concerns above and beyond your oscar fish laying on its side.

Is The Water Quality Causing My Oscar Fish To Lay on Its Side?

Oscar fish require warmer waters at about 75-80°F. Any colder or warmer and you’ll see them pout or resist their normal eating and swimming routines. PH balance between 6.0-8.0 75-80°F is also a must. Ammonia and nitrite levels need to remain at 0 and nitrate under 40ppm.

  • Temperature: 75-80°F
  • PH: 6.0-8.0
  • Ammonia & nitrite: 0
  • Nitrate: Under 40ppm

Water testing kits are a must. A heater and filter must be working properly and not fluctuating. Water changes every other day at 25% or more will also help. Do all this and see if you can restore the mood of your oscar fish so it won’t sulk and lay on its side so much.


Should I Be Worried About My Oscar Fish Laying on Its Side?

No. Don’t worry. Be confident as a fishkeeper. You have a keen set of eyes and awareness to notice multiple factors at the same time. If it’s only the “laying on its side” issue, then it’s ok.

If your oscar fish takes breaks, lays on its side then darts back up to eat, play, swim around or move things around, then all is well.


The simple act of laying on its side is not enough of a reason to be concerned about your oscar fish. You can check for bigger issues in their health by other behavioral actions or external problems that may show themselves on the body of your oscar fish.

Stay observant and take breaks once in a while the way your oscar fish does. Sometimes we just have to submit to nature when we aren’t able to control everything. This is a good lesson to learn from oscar fish.

Brian Arial

Brian Arial has kept fish for leisure and worked with fish stores for most of his life. He enjoys writing and caring for aquariums and ponds.