My Amanos get berries on a regular basis, when they release them its a feeding frenzy for all the fish. Using brackish water to get them to maturity can be done but not easy, there are a few threads with folks attempts on forum.
I recently discovered that the larvae can actually survive for longer than people often think in fresh water but they do seem to eventually need salt water after a max of about a week. They never last more than 24 hours before they're eaten by my fish though.
I once saw a very long and pretty heated debate where someone with a lot of amanos was absolutely adamant that if there's appropriate food then at least some larvae can complete their lifecycle in fresh water as he occasionally had small amanos in their adult form turn up in some of his tanks. Ive seen credible people claim this is absolutely impossible though but find it hard to imagine someone would go to so much trouble to trick people into believing that 1/1000 amano larvae can survive in fresh water and they definitely werent misidentifying their amanos.
I had a big hatch recently that all got eaten very quickly but I live near the sea and it made me think I should chuck them in a bucket of sea water next time and see whether I can raise some up.