I am super curious if the person still has this snail. I just also bought a brotia herculea and am compiling research on them. Surprisingly little is available in english but i will come back with info once i have it.
So, anyways, really not that many information in english but we had a nice article from a person who bred them and she also translated some german texts available about them.
While brotia and tylomelania are closely related, they differ greatly in their native environments.
Tylomelania live in large clear lakes with high water temperature of 27-30°C, where water is soft but pH is high, 7,5 - 8. They eat anything, mostly plant matter, algae and the perfecta species burrows in sand and requires soft substrate, while patriarchalis likes stones instead of sand. They produce smaller litter of offsprings that are large in size and fully developed.
Brotia species is found in fast streaming rivers, including waterfalls but over most of south asia. Their water requirements are therefore vastly different, even between members of the brotia family. Overall they need colder water than tylomelania, though nothing is exactly specified, it is operated that standard fishtank water temperature will do and 24-25° is the hottest they can take, it should not go above this. They are mostly found on stones and pebbles, only few species are found in mud and sand.
They do not eat algae, they eat biofilm that appears on the stones, in the mud and some species also eat wood (like B. henriettae). They are all considered primarily detritus eaters (so exact opposite of a nerite snail).
Most often species found is B.pagoda, but they are often other species sold as pagoda, since the differences are quite small and hard to notice in juveniles.
While they may produce large number of very small offsprings, they are very sensitive and rarely survive. The species needs highly oxygenated water with high water flow and specific diet, so while the adults will survive a lot, their offsprings wont, so no need to be afraid of overpopulating.
All the texts say that brotia do not eat plants (unless really hungry) but the first thing my snail did was eat my ludwigia stem, so I guess it was hungry