The United states of America is flooded with bulk plastic tanks that are 275-300 gallon in size. They are surrounded in a metal tube shell and durable plastic liner with a 2 inch drain and large top cap.
these tanks are used by the food industry and appears many are not re-used. New that can cost over $300 each, used has a common price of $75. No need to ever use a toxic tank and those are normally disposed of by the factories, but the people that sale used stuff, almost always only have tanks that liquid food came in, such as honey, vinegar, pop syrup, sugars of all types and the food industry uses them by the thousands.
Creative people are using them for everything from mini gardens, green houses, dog boxes, water storage, etc.
They make a great fish culture tank. 1 tank you could raise about all the fresh fish you would care to eat each year. You would only use a tank method if you lived too far north or you just have no ability to build a small pond on your land. Some people taise allot of fish for resale out of their garage and never have a pond, but a pond is by far the easiest way to raise the babies.
The tanks are best for winter use, keeping the select fish inside a barn or garage so they will continue to grow to proper size. Some fish are like farm animals, in that they grow to a useable size in 6 months to 1 year. Those living in warmer climates can fish year around. Many cultures use allot of fish in their diet because it is cheap meat.
ALL fish that lay eggs, lay allot of eggs, some species actually lay more eggs than you can count........some will say as many as 1 million eggs per summer, but 20,000 would be a more believable number. IN NATURE, out of 20,000, maybe a dozen reach adulthood. IN A FARMING OPERATION, maybe 90% reach size to eat and the cheapest food meat wise. Humans love meat---don't be fooled by those that swear they are vegans---vegans eat more worms than meat eaters, for the simple fact they eat far more raw foods and vegetables are not only loaded with parasite eggs, they are also wrong size minerals.
TREE FRUITS are the only proper human foods, everything else is an adaptable option.
What they call pan fish; is what poor locals world wide eat------PAN SIZE FISH fit in the pan---- these fish can weigh 1# in 6 months of warm water if they have food.
A gov commercial fish farm could raise millions of fish fast and feed an entire state---------but you never see one.......wonder why? Maybe because the ones that built the colleges first were beef and pig farmers?