Killer hermit crabs

I think I am going to adopt that same attitude on them. I'm glad that I took them back, I don't miss them at all!

 

A three month old tank won't support your mandarin or scooter. It will take months for them starve.

 

How big was the tank? There probably was too much competition for the same small amount of food. I never have had problems with my red legs, blue legs, or 2 golf ball sized thin striped hermits but I do put some algae wafers in the tank for them a couple times a week, and started adding them after the tank had been running for a year or so.

The lfs doesn't seem to know what they are doing, or at least only care about sales. You shouldn't have the scooter or the mandarin yet. One will starve in a new tank, let alone two. I doubt you have a large enough tank + refugium setup to house both even if matured setups either - most people don't. They'll just starve to death over many months which can't be a very fun experience.