Oscar Fish Care Sheet



Oscar, photo by Daniella Vereeken
  • Scientific Name: Astronotus ocellatus
  • Lifespan: Approximately 10-15 years if proper care is given
  • Size: Approximately 12-13 inches
  • Care: Easy/Medium
  • Community: Yes, as long as you have lots of room for them to move around.
  • Lifestyle: Diurnal, active during the day.

Tank Requirements

  • Minimum Tank Size: 75 gallon tank for one oscar and 125 gallon for two oscars; bigger is always better.
  • Water Temperature Range: 75 – 82 °F
  • Water pH Range: 6.0 – 7.8
  • Water Hardness Range: 5 – 20 dGH

Perform a 10%-25% water change weekly. If you do not have a filter in your tank, do a water change twice a week.



A hood is recommended as it aids in helping your fish stay in the tank. Also, the hood keeps debris or dust from falling into the tank.


For Lighting: Full spectrum lighting – T5 is recommended.


Every fish and tank is different, so it is important to know what your dealing with. Some fish love a lot of current and others love no current at all like bettas. Some fish tanks are tiny and some are huge. Knowing what you have, or what you are going to have will help aid you in deciding which filter to go with. Check this article here to select which filter you should go with.


The way you are going to want to set up your oscars tank is in a clean, nice, and plain way. You are going to want to stay away from small ceramics, live plants, and products with sharp edges. Oscars love to rearrange everything in a tank if they can which is why ceramics are not a good idea to be put into a tank. They will most likely be flipped over or broken from being moved around all the time. Another thing to know about oscars is that they are very clumsy fish, meaning they will run into pretty much everything which is why no products with sharp edges should be put into the tank. Oscars have a habit of scratching themselves and ripping pieces of flesh off their skin if the right products aren’t being used in the tank.


This doesn’t mean you can’t use anything in the tank. Because you can still use a lot of things, like fake plants (preferably made of silk), driftwood pieces, and large river rocks. These are all great things to be added into the tank to make the environment a little more habitat like for your oscar. When choosing fake plants and driftwood pieces, make sure to choose some that have a heavy bottom so that they can not be moved around so easily by your oscar. Adding driftwood to your enclosure adds two beneficial aspects.


1) Plecos will love it (if you have any) and will spend most of its time scraping algae off of it.

2) The tanins in the driftwood tend to buffer the water to the lower pH range that Oscars prefer.


The primary component of your Oscar fish’s diet should consist of a quality pellet. A few times a week, as a treat, you may offer some meaty foods which may consist of live silkworms, ants, bloodworms, crickets, and etc. Never EVER feed your oscar a goldfish. Its a huge NO NO. Goldfish are very unhealthy for your oscar and may cause diseases.

Feed as much as he/she will eat in 3 minutes.


The best substrate to use for an oscars tank would be large river rocks, large river rock gravel, or nothing  (barebottom).


Note: The information on this oscar fish care sheet is not a substitute for veterinary care.

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