IME they thrive in planted tanks. Maybe thats because there is abundant algae, besides what they get from us (algae wafers, etc...). I have some in 2 of my planted tanks and the ones in the 55g I've had for atleast a year and a half......maybe longer. I don't see them all often, but every now and then I'll see all 3.
Alot of it has to do with shipping them and they are sensitive to begin with. They don't belong in new tanks....I'd say your tank should be setup for atleast 7-8 months and stable before you introduce them, but even then they have a chance of dying. I've lost a few in the batches I've bought, but I guess I'm lucky with the ones I have (3 in one tank and 5 in the other).
