OK, my arm span is roughly 6ft. I can comfortably turn around in about 2 ft. I am human so i would expect better care than a fish. So......a 18-24" aro........in a 18" wide 125 should have no problem whatsoever turning around. It doesn't cause us discomort, and we arent even designed to flex like they are. From above, silver aro's skeletal structure is very similar to a snakes, meaning they are very flexible and can easily maneuver in tight spaces, kinda like during the flooded season in the amazon where roots and dense forests are all they know. I guess this may seem like i am rambling for no good reason and im sure bderick67 will have something of his expertise to say, but i guess everyone should get down off their throne and quit acting like they have never done anything thats not "accepted" by the "experts" on MFK. The sad thing is that i bet i've been keeping fish since most of you were born.
its only your rediculous 5-7 year aproximation which is completely off. 5-7 years later your 2" silver is already at 36" LOL, how the heck are you suppose to fit 36" in 18" of space? Now please don't tell me 36" is completely fine in 18" of width LOL. I really don't see anybody trying to get ON the throne...Sorry pal, your 15-20 years don't match up to my 30-35 years of fish keeping, so to make it simple, no, you have not been keeping fish before I was born.
I was going to reply with much the same...his example has the relative dimensions all wrong...it'd be like living in a space where the ceiling was only 4' tall...