These tanks are often used for holding live rock, vegetation, tropical fish and lobsters. Made for use with fork lifts and pallet jacks, so they do have uneven interiors. Lead time two weeks.
Mini is capable of holding 650 lbs. Stackable, but not nestable. Outside dimensions are 55" L x 30" W x 24" H. The optional heavy-duty lid (L100) weighs 17 lbs.
Middy is an extra-heavy-duty tank that can hold 1,200 lbs. There is no optional lid, but they can be stacked when holding lighter loads (not nestable). Outside dimensions are 50" L x 38" W x 22" H.
Schooner is only 14" H (outside), but can be just the right thing for your aquaculture applications. It can hold 400 lbs, is stackable and no lid is available.
Can be moved with a pallet jack