I just got a fire fish too. Two things with my new little guy:
1. He's a good dither fish in that he likes the channel in back along the wall. I have a cube and left a pretty big back channel so water can swirl around the tank, problem is, the fish never ever go back there. But for the fire fish it's home and it's bringing the other fish back there in their travels, so that's pretty cool.
2. He's dumb as rocks. I have to drop pellet food right to him, and he can't seem to get the concept of "here comes food", rather, he just floats there like an air head and when it's in front of him, he eats it. But if it gets a little behind him, he's clueless, and unless I make the effort, I'm afraid the thing is going to starve because he'll never figure out the feeding ring and that the others are eating.
He's the smallest and added last and got chased around a bit at first, and still gets shown whose boss, but he hangs in there and does come out to play with the others in the front of the tank sometimes. It's weird and random. I've only had him for 4 days so we'll see what time brings. He's pretty and more boring than the others, but per #1, I'm ok with him. His colors make for a great display when all the fish are together, and he is kinda cute when he peers at me with his big eyes, which he does- he'll turn and stare. Someone else here said that too.
There is also such a thing as too much activity. My clown fish is driving everyone crazy. He's constantly sprinting all over the tank. I don't know where he gets his calories but that fish needs some massive ritalin doses.