Saigon Aquarium’s ‘small farm’ raises about 100,000 Corydoras catfish per year. Green, albino (both C. aeneus I presume), panda, and sterbai.
There was a bit of a language gap between me and the tour guide (mostly due to my being too excited to speak slowly) and a BIG language gap between me and the breeder, but the system seemed pretty straightforward. Large groups of big, fat adults live in small open-top tile ponds. Water hyacinth floats in the ponds with the adults, and the roots inevitably become thick with eggs.
The hyacinth is moved onto small hatching tanks, and then the fry moved to successively larger grow-out tanks until eventually they’re turned loose in their own small ponds. Then, when the shop gets an order, groups of young adults are netted out of the ponds and moved back into glass tanks for a few days of inspection, sorting, and quarantine before shipping out.
(click photos to enlarge)
Only some of the breeder ponds had hyacinth in them. I asked Binh for more details about how they decide what numbers to raise of which species, and he said they’re in constant communication with their wholesalers and that they don’t always raise as many fish as they have capacity for. It seems logistically complicated to me, having to predict demand many months down the road, but I suppose that’s true for any kind of farm.