Actually when I got him, He was the same color he is now... He was yellow, had black verticle stripes, but his fins were all vibrant blue tinted... Tehy change from yellow to blue back and forth.. I hav noticed he is a bit more on the aggressive side but he liked to stay under some eel grass I have. He loves to eat and he literally will jump out of the water to grab some food. It's the neatest thing to watch. Once I get my 75 Gallon tank I am putting him in there to live out life and plant it well, and find a nice female to add in as well.. I really love this fish.. ;-)
I have noticed when he switches into agressive mode, his colors become really visible, bright, and stand out. His fins go blue and and stripes get darker.. He does this when it comes around feeding time too once in a while. I'll snap a picture or two next time I think of it..