I'm sure you are aware aros gro at a very quick rate initially but after that first 24" they sort of slow down.. so look at aro keepers who have had aros for a long time.. not sure how big bderick67(brian) aros are.. he might chip in here.. i've had my aros a little over 2 years now.. the only hassle is measuring them.. the stress involved to the fish keeper and fish is tremendous.. as in to catch and measure.. if its a glass tank i agree you can sort of approximate and say the fish is x ft big.. but then refraction plays a big part.. i use the tiles in my pond as an approximate measure.. the tiles are 1X1.. so i assume the fish are close to 28".. but i know they are prob a little bit bigger than that..