I had a 20 gallon that was well cycled and had some neocaridina davidi (red, blue, yellow, orange, green, blue rili, red rili, all sorts of kinds) and they all died, my nitrates were low, my ammonia was low, I had in food and drift wood and all sorts of other stuff and they still just died off, any ideas why? I want to know because I might start up another shrimp tank, should I keep only one type of shrimp (like only red cherry shirmp) or can I mix them? my main worry is just making sure they'll live and reproduce