That peacock is a smasher, and I doubt it can punch through that tank. I've got a 5+" peacock in a 12g eclipse and it has punched the tank sides a few times, but never gone through it, or even scarred the tank sides. Currently I'm looking for a bigger tank for this guy - thinking about a glass 30 cube, though all I really want is a glass 20 high, but according to Dr. Roy, glass on a 20 has the potential to be broken by a peacock.
Spearers don't smash tank walls, smashers do. Glass tanks are in danger, not acrylic.
Ken