oscar acting weird

Question
is it normal for my tiger Oscar to change from purple to like yellow and start shaking with its tail moving like crazy and its mouth open likes it wants to eat me? why does that happen or what does that mean?

Answer
Oscars are like mood rings and sometimes change colors like if he is bright he is happy and if his colors are dull he is sad. For the tail moving like crazy and the mouth opens and stuff my oscar does that alot to. If their is a female oscar in the tank or male in with the oscar you have now it might be a dance to attract a mate.

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