Why Do Oscar Fish Change Colors | Aquascape Addiction

Why Do Oscar Fish Change Colors

If you are wondering why do Oscar Fish change colors then this article has the answers, we look at 3 common causes and why it's important to spot them early incase it's something bad.

Why Do Oscar Fish Change Colors

Oscars are some really beautiful and colorful fish. We don’t think that there is anybody who would argue with that. What is really interesting is that Oscars are not always so bright and colorful. What we mean to say is that they can and often do change colors.

Some people who have no owned Oscars before find this to be quite disconcerting, as many people automatically take it as a sign of illness. While this can be true in some cases, most often it is not. So, why do Oscar fish change colors?


The first reason why Oscars change colors is due to age. This is a fairly slow color changing process, but it is definitely noticeable if you pay attention. Oscar fish are not born all that colorful, they are actually fairly dull as fry.

However, as they age, they will begin to develop more colors, they become brighter, and various patterns become more pronounced. There are some similarities between various Oscars, but many of the mature in different ways. Not all Oscar fish develop the same colors or patterns as they age.

Mood Swings

Another reason why Oscars change color is because of the mood they are in. It’s an emotional kind of thing. Once again, it is hard to describe exactly which colors an Oscar display in correlation with any given mood. Oscars are all different, and while many of them may display similar colors in relation to their moods, it can vary quite greatly.

Generally speaking, a happy and relaxed Oscar fish will be fairly dark in color, usually black, blue, or dark green, more or less a dark shade of their original color. Now, when they get angry or upset, they tend to get really bright in color.

They may display bright greens, blues, reds, and other really vibrant colors. When they are sad or anxious, they may display paler colors like a pale green, blue, red, or any other pale color variation of the colors they already have.

Health & Water Conditions

The final reason why your Oscar fish might change color is due to its own health or due to the water conditions. Generally speaking, a healthy Oscar fish will display fairly bright colors, whereas an Oscar that is ill will usually be much paler in comparison.

At the same time, closely related to the health aspect, Oscar fish usually exhibit dull colors when the water conditions are not up to par (more on how to check water quality here). If your Oscar is brightly colored, it is most likely healthy, happy, and living in good conditions.


As you can see, if you Oscar is mature, healthy, and happy, it should be fairly brightly colored. However, emotions such as anger and anxiousness can cause this to change. Their age also has something to do with color change. This is an interesting scientific phenomenon that requires some further research.