Red-footed hermit crabs

[sighthoundlover]

Can anyone tell me how long one would expect a red-footed hermit crab to live? I ask because I started out in February with 30 but I don't think I have that many anymore. I have a 75 gallon tank with live rock, a very healthy and gregarious cleaner shrimp, a happy, beautiful royal gramma, a bunch of fan or feather-duster worms :?: and a true ocellaris waiting in my quarantine tank to join the big tank. I have a lot of coraline algae and some of the crabs are encrusted with it. There's no hair algae at all in my tank. There's generally a very light amount of brownish algae :?: on the sand in a low flow area by the time I do my water change every two weeks. I'm trying to figure out if I should get more hermit crabs or if there isn't enough for them to eat so getting more might be a waste of money and life. :? I'd appreciate any comments.
Thanks

 

[Len]

If my personal experience is accurate, hermits really don't live very long .... a couple of years or so. If yours are disappearing that fast, however, I suspect either they don't have enough to eat, aren't agreeing with some parameter of the tank's water, or something is eating/killing them. In my tank, I can never keep hermits alive for more then a few weeks due to fish and a resident mantis eating them. My opinion is they aren't needed for a sucessful, algae-free tank and I wouldn't get more for your tank.