Fish vs. Rocks

[mpjmeyer]

OK So after over a year of collecting, saving up for and planning equipment, I finally am going to start filling this tank TOMORROW!!! Finish plumbing the tank tonight and start the RODI to fill up my mixing station. I was thinking of making some minor changes in my rock structure, but have a couple questions first.... My tank is a 65 gallon so I don't think I'll have any large livestock

1. What is an ideal size gap for most fish to swim through?

2. How much force could fish put into a hit if they accidentally bump into a structure? Is it possible for a fish to destroy a rock structure? Each rock I placed, I wiggled it a bit to make sure there won't be any boulders falling on the fish. Anybody have any incidents where fish caused rock to tumble on themselves?

 

[mpjmeyer]

 

[ahiggins]

Youll be surprised how tiny the holes are that they can get through lol
Your scape looks great :)
When I do my rock work, I do the exact same. I wiggle to make sure that "wiggling" cant make it fall (and it helps since live rock naturally wants to fit together).