You need lots of tanks if you want to do efficiently. Or just get a large vat of some sort (is that an IBC tote?) but if you use that method, one mistake, or disease and you lose a lot of fish. I'd raise them to 1cm and then move each brood to its own grow out tank until you run out of grow out ...

I have a 182L(48g) 120cm(4 foot) tank that I plan to put 2 male and 2 female Longfin Super Red Bristlenose in to breed. Stores in Australia sell them at 5cm (2 inches) for $145 a pop and 2,5gm (1 inch) for like $80. The physical stores however have no stock. Given that I need the parents to be in ...