Dwarf Blue-Leg Hermit Crab, Reef Safe?

[ech0o]

I was chatting in TFF chat the other day and Techen mentioned he thought he remembered something come up in the past about the small blue-leg hermits being dangerous in reef tanks.   I just wanted to make sure they would not be an issue as I have 4 of them in my 26 gallon reef.   They are super tiny and very cute, I couldn't imagine them hurting anything else in the tank, can someone clarify?  Is there a larger blue leg hermit that was maybe confused with?
 
I do have an emerald crab in the tank which I have heard could be an issue if the algae runs out, but the cycle is not fully complete so we are still getting a good amount of diatoms and there is ALOT of hair algae, so it should be some time before he runs out of food source.
 
In the tank right now
aragonite sand and crushed shells/coral substrate
12lbs fiji liverock
6 lbs totoka liverock
2 colonies of green star polyps
1 lyretail molly
4 dwarf blue-leg hermits
1 dwarf red tip hermit
1 emerald crab
2 turban snails
 
just trying to keep everything rolling as the cycle stages progress, I was at the hair algae point before we converted the 10gallon tank into the 26 gallon, now we are back to diatoms so i tried to put in a nice diatom cleanup crew, although the emerald crab hasn't emerged yet, has been in the tank for about a week now.  i figure as soon as the hair starts growing again, i will grab a small lawnmower blenny, the really seems to be missing a blenny.
 
my tank levels
ammonia 0ppm
nitrite 0ppm
nitrate 2ppm  (my nitrate never seems to hit zero, but I have yet to build my protein skimmer, so i figure for it to never really climb above 3ppm is pretty good?)
phosphate/silica (no test equip for these yet but i suspect there to be a slight issue due to the amount of diatoms)
 
 

 

[Donya]

Small hermit species are incredibly common in reef tanks are considered by many to be a pretty critical part of a CUC. Yours will be fine if provided for properly. There are a few exceptions where hermits can be problematic for climbing on fragile things or stomping on them, but that is largely avoidable by careful placement of things that shouldn't be trampled. If small hermits terrorize an average reef tank, something has gone wrong.
 
The bottom line with hermits and Crustaceans in general is that if you don't care for them properly, they will do their best to care for themselves at the expense of your tank. Most problems with small hermits are due to lack of suitable spare shells, wrong diet/insufficient food, overcrowding, etc. Other contributing factors to behavioral problems are wrong IDs and mixing inappropriate species (Clibanarius tricolor + Paugirstes cadenati = hermit war in many tanks). Bigger species are another matter, since they can sometimes cause damage to things just from being clumsy even then they are otherwise peaceful.
 
 

Is there a larger blue leg hermit that was maybe confused with?

 
 
Usually "blue leg hermit" refers to Clibanarius tricolor, which stay reasonably small (max of ~1" shell length) and are one of the more commonly used CUC animals. Calcinus elegans is another blue species, usually called electric blue or blue striped, but grows larger and is potentially more problematic due to the max size and claw morphology. 
 
 
 

I do have an emerald crab in the tank which I have heard could be an issue if the algae runs out

 
 
Emerald crabs are not herbivores despite commonly being sold as grazers. They eat a lot of algae, but they are still omnivores and can therefore be a problem if they don't get meaty food periodically even when there's plenty of algae. 
 
 

nitrate 2ppm  (my nitrate never seems to hit zero, but I have yet to build my protein skimmer, so i figure for it to never really climb above 3ppm is pretty good?)

 
 
Many mature tanks never stay that low once stocked. Unless you're aiming for an ultra low nutrient system, even 5ppm is considered pretty low for most systems. 

 

[ech0o]

Perfect Donya, thanks for the info, I hear your the go to lady for crustaceans!!

 

[xXLeafeonXx]

+1 to dwarf hermits being harmless.

 

[BigTuna]

I have a pair of larger Calcinus elegans in my tank, and they are incredible.  I have yet to experience any issues with clumsy behavior.  Rather than clipping dried algae and seaweed strips on the side glass of the tank (for my tangs) I try to spread chunks of it throughout the tank pinned between rocks. I am sure the crabs appreciate the variety available to them.  They are one of my favorite habitants in my tank so far, and are often the first two I look for to greet in the mornings.