i have a 300 gallon stock tank like the ones pictures above and they are tough!!! thick!! and they arent that heavy. i have an 18 inch (shell Length) alligator snapping turtle in one. he has been in there now for 3 or 4 yrs (i forget) and he has scratched and scraped and not even close to puncturing it. even if the rb's can get a tooth on it i think the stock tank is way to thick for them to puncture. i bought mine at that fish store in occonomowoc that sells tank a dollar a gallon up to 55 gallons!! i saw them using it as a feeder tank (there was 3 gold fish in it) and i asked where they got it from and how much. they said if i wanted that one i could have it for 145. i took it! lol but yeah, look at the fleet farms and the tractor /farm supply stores like someone suggested

