10x5x2 would be as small as I'd go for an adult niger catfish. 100m by 50m would be a ton of space though!No, I have a 10x5x2 pond. It will soon be crowded though. But I have plan on turning my unused swimming pool into fish pond. If it still crowded, I could just throw em in my 100m x 50m pond. Make a fishing pond, sorta.
Its easier if I just show you the thread
https://www.monsterfishkeepers.com/forums/threads/speaking-of-tsn-runts-dinks-and-co.673687/
You could also use an above-ground pool - at least 8' diameter, preferably 10'+. Just make sure to use a 45 mil liner in there above the stock liner.
Drew