Adult Tiger Oscar In a 35 Gallon?


Hello everyone
i've been doing a lot of research on tiger oscars lately and i've got one more question for you
i've read all about them being okay, and not okay in a 35 gallon tank, that they need frozen food as opposed to live food, they can grow to 12 inches but some say they've gotten 16 inches
there are so many different opinions so my question is:
will an oscar be able to grow to 12 inches in a 35 gallon tank?
most fish only get as big as their environment allows so my question is just simply can it reach full size in 35 gallons or will it get stunted at 6 or 7 inches
please not comments on how terrible it is to keep them in that small a tank or anything because i've got opinions and arguments from both sides coming out of my ears right now so it'll just go right in the ol opinion box
thanks everyone


fish getting as big as their enviroment is a myth, it can cause them to become deformed... you should google s of it, its some nasty stuff.. id adivse at least a 55 gallon... 75 even better. GOOD LUCK!


60gals is a general rule for 1 oscar, there are also dimension limits as well. Due to their high bio-load and activity level and size, a 35gal will be no where near enough space for them. 12inches is a good minimum for an oscar, they can reach that in the first 12-16 months of life, 15-16 would be a good average imo.


You really need to get up to at least a 55 as mentioned. They are a VERY messy fish and will produce a lot of waste that a tank as small as a 35 just won't be able to handle even if you put a ton of filtration on it. Ok well maybe the filters could keep up but I don't think the oscar would like to be swimming with that much current in the tank.


Oscars are a fish I have researched extensively. I would advise a 55 gallon minimum, 75 gallon or larger is optimum due to my research and experience.

They are a fun fish and definitely a great species to keep!


No, an oscar will not grow to 12 inches in a 35 gl, it will become deformed and stunted. +1 to all the above.


I agree with all above posters. "Growing to the size of the tank" simply means becoming deformed and having a shorter life. Oscars get way, way too big for a 35.


People often think that stunted growth simply means the fish doesn't get as big, but that isn't true. They grow disproportionately (I've seen pictures of angels with enormous eyes from being kept in tanks much too small).


There was a similar post about this but ill recap my info.

I had a clownknife and two oscars in a 55 gallon.not my fault it was a rescue and I felt like the oscar needed a friend. I was wrong. I cleaned the tank every two days and the gravel was filthy. This is how the fish behaved. Oscars constantly fought jaw locking and had bruises fin rot and ich. And the clown knife only would stick his head out when I would feed him( had to stick my hand infront of his face just to get him to eat. This all lasted for two months. I had ich numerous times.

Than I got a 160 gallon and moved them over. And within two weeks all bruises dissapeared. The oscars turned a dark black and more orange came out. They have stopped fighting. And the clown knife is constantly out. So in my oponion I would say a 75 minimum for a 100 plus for two. Side note you will need about 8x tunrover for oscar tanks
  • Thread Starter


thanks for all the posts everyone
very VERY helpful
i'll be taking note and plan accordingly
probably upgrade to a 70 or 90 gallon
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