The plastic on my pond is kinda thick like 1/4" thick, and there are no seems so it must be vaccum molded! It is inside also so no UV damage. i think it should last a while and if you are not totally comfortable then put a liner in it, but mine works fine! Here some pics for ya! If you see from one of the pics you can see the side view of your catfish just fine! i haven't had a problem yet. I feed the biggest one first, he's about 28" right now, and then feed the other ones! If you see though catfish look beautiful from above! Especially a TSN. Mine is 350gal., and I don't think i need to upgrade until the big one reaches more than 4', even then since it is round instead of squaure he'll have no problems turning around, and as for swimming space, well I solved that by putting my filter intakes sideways and letting the water whirlpool in a circle. when they do decide to swim they swim against the current in a big circle for hours(kinda like nascar). So don't worry so much and go to your nearest farm supply store and ask to look at their cattle troughs. Mine had sizes up to 12' dia, but only the 6' or 4' dia would fit through my doorway! They were all 2' tall.
