Not really looking for tankmates. Just the four snakes in a large aquatic setip 

What about stocking large feeder goldfish, but keeping them and gutlaoding them for a few weeks before feeding them to the snakes? I feel that would be much more manageable. Maybe even hiding pinky mice in large pieces of fish fillets?
Side note: That last paper I link to has the nutrient composition of fish in Bangladesh, which incudes genera likely eaten by H.buccata in the wild, possibly giving you a closer idea to what they might require, albeit not exact as it may not be the specific species/habitat, and it only has some crustacean and no amphibian info. It's also excluding bones, organs, fins, scales, and gills, which would increase some levels quite a bit.
No never do this, goldfish contain a chemical which at first leads to retardation like behaviors in reptiles, this along with the thiamase issue will lead to the death of your snake.What about stocking large feeder goldfish, but keeping them and gutlaoding them for a few weeks before feeding them to the snakes? I feel that would be much more manageable. Maybe even hiding pinky mice in large pieces of fish fillets?
If you want a better understanding of why goldfish are bad for these guys, there are parrarels in wernicke encephalchy (spl?).No never do this, goldfish contain a chemical which at first leads to retardation like behaviors in reptiles, this along with the thiamase issue will lead to the death of your snake.