they can grow a few inches more larger than 7, depending on what you're keeping it in. It sounds like you've got a good healthy place for it if its up to 7 inches. What size tank are you keeping it in?
Mines about 5, hes in a 20 gallon for now until I move next month. I was really happy he survived because I never expect carnival fish to survive, he was a little beat up when I first brought him home.
**** I wanna say a common because of the short tail and also on shbkns the have a blue appearence to there body, but commons dont really get that type of coloring very possible hes a mix.
My shubie Fuzzy that I used to have was over 12 inches in total length at the time she passed away. They can get quite large with the right growing conditions.