Is that the current tank they're in and with fry? They don't look too stressed, and if they've spawned, they must be reasonably comfortable. That said, I think you've got a lot going on in that tank. I would keep a close eye in your ammonia/nitrate readings. With the number of fish and the gravel, you could be building up the dissolved organics in the system. (Keep up the water changes) With 100% RO and that pH, you could be susceptible to a ph crash eventually. pH doesn't need to be low, that's an old idea. If it's steady and they're used to it, that's what matters. Mine is 8+. That also means there's some carbonate to stabilize the pH and for the bacteria to feed off of. Your foods are fine, as long as any leftovers are getting cleaned up.