Some types will go for years without a problem, a teacher I had kept some in a cool water tank with mudfish and killies, his were an encrusting type. Most are small, an inch or two but at least one can reach more than 3 feet long, I think that one is a cold water, clear lake species. Her are pics from various sources of some different types, They are from several places including New Zealand, Canada, Georgia, and Alabama. The one with the zebra mussels is from Lake Erie.











