Mines around 11" and gets along with both my 7" and 9" sens. The 7" sen is really small compared to him but they never seem to get in to any fights, no chasing no biting no anything. Even during feeding they dont mess with each other. The only problem I had was with my pleco being territorial chasing others around. But now Ive removed the him so everyones fine again.
You'll love yours. Mines pretty active even when lights are on, he doesnt hide as much because I took out his cave. He swims about most of the time and happily displays himself. But I think you should quarantine yours first before you add it to your tank. Might have some parasites. Give it a simple salt bath to get rid of external parasites.
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Mines really green but doesnt have a really distinct pattern. But thats what I like. 
