When I was breeding Neos - I had very large colonies of Black/ Chocolate, Rilis, Reds, Blues - I bred them all in soft water. I never had any issues with survival rates in fact they bred extremely well and were of a very high standard. The main thing is to ensure you have moss for them to hide in, feed lots of powdered food and keep stable parameters. I have bred them in ph of 6 , GH 6. KH 1-2 TDS 150-160. I kept 10 tanks of mixed bee and Neos for several years I used RO water with GH+ and benibachi substrate. I also used mineral powder weekly , biozyme twice a week, 5-10% water change. As always I believe stability is the main thing we need to look at . Check water parameters before adding to tank, keep temp of new water close to temp of tank, good quality foods.