Hmmm, food for thought. Yes, I own a 20g and maybe there simply isn't enough food supply for them or they are dying of the tank conditions, which are within normal limits, but who knows? My fish and crabs are thriving and feeding voraciously.
The snails are all types...turbos, Mexicans, and one or two other types. The Mexicnas are hanging in...the turbos went early. The mixed types are getting mixed results.
Thanks again guys.
...No seriously, I don't know what I'm doing.