How fat should Lawnmower blennies be?

[my2rotties]

I know it's a pretty silly question but Waldo my LB is a porker. He is so fat his little flippers to each side of him hardly reach below him. When he's on top of rock and the wavemaker turns on, he almost tips right over...

He is healthy active and happy, but he was much skinnier when I bought him. Just checking if its okay or if he might have something wrong with him. Obviously he eats a lot but since he is my first LB I don't have any others to compare to him. He is such a fun fish and I'm sure glad I got him.