Then all those people with stock tank ponds are wasting there time too? this is a stock tank rubber or metal. They make great ponds inside and out and lets people keep some fish they would normally not. the 300 gallon one is popular especially with south american cichlid keepers. I have a 110 and a 150 on my patio. I have not filled the 150 but im going with africans with strawberry pots all in it. the 110 has a 2 inch id shark, 2 silver dollars from inside, and 2 small pink convicts. I am going to get two oscars. The Oscar will do a nose dive out of it jumping to catch the bugs. I have found this out the hard way. As for heating, a aquarium heater and a tarp will do WONDERS. Down in South FLA, we got into the 30's for three nigths in a row. kept the stock tank covered with a tarp and the heater running and everyone did FINE!