Sweet blenny!! I've been looking for one of those for ages.
Tank looks good. Yeah, you'll be surprised how much those rocks shed.
I'm sure you just placed it there temporarily for now, but I'll suggest anyhow you move the clam or build a little rockwall around him, it's only a matter of time before he rolls off there. The perfect spot, I've found, is a sort of cup shape or indentation where it's a little uphill all around, that way they'll feel good and secure. Hard to tell from the photo 100% but I think I spy a spot just to the left of your green/yellow acro there that might be perfect (or might be perfect with some rubble epoxied in front). Sorry I hope I'm not coming across as a poo poo head for making a suggestion
The aquascaping looks great.
And I'm real jealous of the blenny!
More pictures of him when you get a chance, please!