Rainbow Darters Aggressive

This is my second round with keeping rainbow darters and a first for seeing them fight. I wish I had a video camera but I do not. They are nipping each other when one enters another's real estate under the driftwood. Prior to adding these rainbows I had 3 fantail darters and they claimed their spots and made it known when the new darters entered them. After researching I figured with enough in the tank they wouldn't become as territorial but to the contrary with the exception of the log perch every one of them have claimed spots.

One rainbow is homeless and been trying to overtake a bigger one for his spot but to no avail every time. I have to give him an A for effort. He won't give up. He tries everyday. Kind of entertaining to watch. No damage from what I can see.

I searched through the forum and found no other posts regarding this behavior so I am wondering if it is a unique occurrence.

I'm not as much of a seasoned veteran as some others here, but I have kept up to 8 Rainbows at one time before. I have never seen rainbows being that aggressive or territorial with each other. However, the interesting thing about natives, compared to tropicals, is that they each can have a different personality and you never know what your bringing home. My 1st Striped Darter was VERY territorial, but the one I have now isn't and is very community based, you just never know.

If this continues, you could give them some rock structures, caves, etc... to give each it's own area.