Do you have a TDS meter and RO water? A TDS meter measures total dissolved solids and RO water is reverse osmosis filtered water. Also, you will need a mineral additive for shrimp. Shrimp are very sensitive. Neocardinia’s are more tolerant and good for newbies, but cardinia’s are very sensitive. Also, get a PH meter. I paid around $10 for my meters and they’re good enough. If you want to try again, I recommend making sure they’re neo’s. Everything I mentioned I have in my 20g is safe to be with dwarf shrimp, usually. Nothing is guaranteed. You will find lots of information on fish forums, but honestly, those are a joke, especially compared to this forum. People here are polite and seem to actually know something, and if they don’t they say so. At least that’s been my experience. NEVER buy from a chain store. PLEASE.