Oscar fish growth

I have a 75 gallon with an albino Oscar that I got at around an inch long around February of 2017 it’s now only about 8.5 inches it grew about an inch in the last five months. It’s pretty overfiltered and the temperature is kept at 80 degrees Fahrenheit. I do weekly 50% water changes and the nitrates are never above 20. I’m guessing it’s not growing well because it’s very picky and goes days without eating pellets. I also feed it a variety of freeze dried and frozen foods. I also think part of it might be because it was bullied by the much bigger tiger oscars that were in the pet store aquarium with it. It seems happy and healthy but I’m disappointed that it hasn’t grown to at least around ten inches at this point. If there’s anything else I could do please let me know.

LEGO99 said:

It seems happy and healthy but I’m disappointed that it hasn’t grown to at least around ten inches at this point. If there’s anything else I could do please let me know.

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Why are you in a rush for it to grow?

People don't grow at the same rate, and not everyone grows to the same size. It is the same with fish, just be patient, provide the fish with what it needs, good water quality, good food ect and it will be fine. Just give it time to grow, they are pretty long lived fish so just give it some time

As per lumpfish, fish will grow at different rates so not necessarily an issue.

One thing that I will ask though is why is your temperature so high? I'd have it around 75-77 max and a quick google confirms this is optimum for the fish.

I'm not suggesting its suddenly going to put on a growth spurt if you drop it but fish that aren't happy aren't going to be completely healthy.

I keep it at a temperature slightly colder than max because the heater is old so I’d have more time to add my spare one in and I’ve heard that keeping the water warmer helps with growth. And many websites will say that oscars should be close to 10 inches by the time they’re a year old which is why I’m wondering if there’s anything else I can do.

I’m just concerned even though it appears to be pretty happy and healthy

What are the tank dimensions (length x width x height)?
In a small tank the fish will never reach its full size. You need a tank that is 6 foot long x 2 ft wide x 2 ft high or bigger for them to get to full size.

Adult Oscars only need feeding once every couple of days.

I’m not able to obtain a 180 gallon. It’s 48 by 18 24 so I guess it’s actually a 90 gallon.

I got it used and it was labeled as a 75

In a 4ft tank the fish is about as big as it's going to get.

To work out the volume of water in the tank:
measure length x width x height in cm.
divide by 1000.
= volume in litres.

When you measure the height, measure from the top of the substrate to the top of the water level.

There is a calculator/ converter in the "How To Tips" at the top of this page that will let you convert litres to gallons if you need it.

Ya it’s a 90 gallon or 340.687 litres

I’ve seen other keepers with oscars that have grown to twelve inches but they’re kept in 55s which is partially why it’s so unusual to me.