Unlike their dry land cousins, aquarium hermit crabs are usually not purchased for children in the interest of a pet. They are usually sought out to do a specific job. And this job is very important. They help clean detritus and algae from aquariums, in this case, marine aquariums. Aquarium Hermit Crabs are wondrous in variety, and eventually, you will see several species types here, available for sale. The first 2 i have included are the most common, and the most readily available. The Blue Leg and Red Leg hermits offered here are generally very similar, however, it is believed that the blue legs will not become aggressive and kill other snails and hermit crabs for their shells. In my experience, I have seen no definitive difference in behavior between these 2 species. They are usually good for the main purpose of keeping an aquarium clean. Both may have a tendancy to cause trouble in an aquarium once they out grow their shells.
One should understand that hermit crabs and snails, etc are only part of the solution to a bigger problem. This problem is usually hair algae, or excess algae in general. That once sparling tank of yours is now green and brown, and you need to clean it up fast! Be assured, with the right water conditions, the introduction of hermit crabs and snails into an aquarium can be a miracle solution to a huge problem. But it can also make your situation worse. Hermit crabs are generally not sensitive to temperature and light, but in a marine aquarium especially, there are other factors as well that will determine weather or not your crabs and snails will live. There are hundreds, if not thousands, of variables in an aquarium that can affect the appearance and occurrence of nuisance algae. 2 out of 3 aquariums will run fine with little or no maintenance at all. But what about the troubled tanks? This section may shed some light on the fact that hermit crabs and snails may not be doing the job for you that you thought they would.
Water quality, with all its parameters and conditions, is complicated, especially in a marine coral reef aquarium. Each condition affects the next and so on. This is why the hobby is so respected, but at the same time so feared. The problems that arise within an aquarium are usually not due to one factor, but many working against the hobbyist. To list them all is impossible, but keep in mind that a dirty marine aquarium with loads of algae and dying coral, will probably not be helped by introducing a cleaner pack of snails and hermits due to one very important reason. If you add the snails and hermits and they do not survive the transfer, your problem will only get worse.
Here is an important fact. The same conditions affecting your aquarium, hurting your corals and making the unsightly algae, may also harm your hermits and snails. This will compound your problem greatly, as snails especially, are dense with nutrient value and can easily pollute and harm the aquarium life. More information about reef tanks can be found at http://www.reefcentral.com.
Try to make sure that your aquarium parameters are properly balanced before adding any live organisms you purchase from this site. Check your conditions, do a water test. If your putting hermit crab after hermit crab in your aquarium because of algae problems, and you don't own a test kit, please think twice about what your doing. Try to make all your conditions proper before adding more livestock. This is really not that difficult and can be achieved usually by changing one small thing, such as a light timer, additive overdose, or feeding schedule. Please email me with any questions or concerns.
I have over 20 years of experience in the industry and will help you like I've helped the hundreds of others, enjoy their clean, healthy aquarium. Also, please refer to our book section for great books on reef keeping.