Teddy Bear Crab Tank Mates? And Other Questions...

[VickyChaiTea]

Long time no post! So I have this lil' P. vespertilio Teddy Bear Crab. I've had him for about 3 months and he seems to be doing well. I've narrowed his diet down to dried algae and frozen silversides, which he relishes.
 
My 1st question is, what can I keep with him, if anything? I'm not looking for fish, mind you, I want to keep this an invert tank. I also plan on sloooowly adding more live rock, when I get any spare cash.
 
My set up is:
10 gallon
2 Aqueon Quiet Flow 10's, one with a regular filter pad and one with just sponge
50 watt heater
~4lbs live rock
2-3" of live sand
50% water change weekly

 
The crab himself!

 
I've been wanting some turbo or astrea snails, but I have a huge attraction to nassarius snails! They're like crazy little alien creatures. But I'd like something that eats algae. I don't mind scraping it, mind you. I just want something to cruise around and fill it's little tummy.
 
I was also hoping hermits... but I'm not sure if this guy would be too big and predatory.

Another thing I was thinking of is a Sally Lightfoot Crab. Just something to keep the tank busy during the day! I am well aware, however, that I may not be able to put anything in there at all. I just figured I'd ask.
 
I knooooow the sand is an issue (depth), I have been having problems with nitrates. Which brings me to my next question... Would a hang on back refugium be a better filter? Or will simply adding a quality protein skimmer work better? This is my first saltwater tank so I'm still learning. Please excuse me if these questions seem to have obvious answers!
 
Thanks in advance for any replies.

 

[Donya]

How big is the crab right now? I've read an estimated max size for the species as being ~2.5cm carapace length (or 3cm across) which is not too different from some the biggest individuals of other Pilumnus species I have. Size would be the main issue for choosing other animals, particularly if it's larger than those estimates. What I've written below is assuming that it's within those estimates; if it's distinctly larger then the info I've read is off and it's back to the drawing board.
 
Cleaner-type shrimp should be ok, or a few peppermints - basically they are way too fast to be food for crabs like these unless there is something already wrong with them. Moderately-sized hermits would be my first guess for hermits, maybe a Calcinus species like C. elegans. I have Pilumnus species in all my tanks with zero trouble with hermits. Some of the crabs being comparable size to the measurements above with pretty hefty-looking claws, although none are P. vespertillio specifically so to be safest I wouldn't try any really tiny hermits just to be on the safe side. I would assume that something like Clibanarius vittatus or C. striolatus would also be safe if not too small when added, but one of those would also become the biggest thing in the tank by quite a bit. For snails, maybe something like a big Turbo. Safest bet is always for something that would be hard for the crab to pop open with its claws. My other Pilumnus have even been in with quite small Nerites and never shown any interest in snails though.
 
Definite no on sally lightfoots, too aggressive and too big. They are very iffy things in most tanks and accused of savaging many other inverts. I wouldn't add any other true crabs in a tank of that size actually; would be temping fate too much for somebody getting their arms ripped off in a scrap over food. 
 

Would a hang on back refugium be a better filter? Or will simply adding a quality protein skimmer work better?

 
Either that or even an in-tank 'fuge with chaeto would help, just putting it in a plastic breeder box or something to keep the crab from eating it all. You might have a hard time finding a sufficiently small skimmer that does any good; most are meant for much bigger tanks, and the smaller ones are air-driven and not very effective IME for serious nutrient export (I use them more for things like coarser particulate removal). However, you may find that the issue is just that the tank needs more rock. Fish in particular is a very messy food for minimally-filtered tanks. You might try feeding the crab freeze dried krill or something with tongs for a while until you get more rock in there to cut down on the waste production. 

 

[stanleo]

I have no help on this but I have to say it: That crab is ADORABLE!

 

[VickyChaiTea]

Erm...

 
He's kinda big. :[ So maybe no on tank mates then? (please excuse the cloudy water and algae, this is directly after a water change and I'm letting algae grow for any potential snails.) Just put a tape measurer to my hand and he's approx. 1.5" in carapace length.
 
Thank you sooooo much for the suggestions. C. elegans are absolutely goooorgeous. But honestly... I may set up a hermit tank alone- just to avoid any potentialy harm to the crabbies. But that's not likely to happen any time soon.
 
Also, I didn't really think to do an in-tank refugium! Or rather, I didn't know you COULD. I think that's certainly something I could do. That and more LR
 
And yes, he is probably one of the coolest things I've ever owned. I sincerely wish he wasn't nocturnal though! You never see him during the day. He buries himself in the sand or hangs out under the LR. Which is why I was interested in tank mates.
 
Soooooo maybe a cleaner shrimp or some peppermints? Mmmmmaybe a big turbo? We have big (1.5-2") Mexican turbos at work. Would those be ok?

 

[Donya]

Although it's hard to tell against a hand (vs. a ruler), unless you have really small hands that does look bigger than the size estimates I've read. Makes me wonder about the ID a bit, since there are other, quite hairy species that also go under the same common name (and offhand I don't have many good references for any of them unfortunately). It could also be that the sizes in the references I've read are wrong...in which case I would say it's best kept a species tank, particularly in case it molts and grows more.

 

[VickyChaiTea]

Yeah, all the reading I did was about much smaller crabs. But.. he appears to match the description of P. vespertilio. just bigger. I actually had a hard time narrowing down his species/care info since there were so many other crabs called "teddy bears". He is reportedly from a customer who had him hitchike in some rock, lived in the tank for years, then we threw him in our live rock tank. He lived there for who knows how long before I noticed him. Turns out my co-workers knew about him for a while but nobody gave me an answer as to how long. So maybe he's just really big and old?
 
I can break out the tape measure tonight and see if I can't harass him (her...?) into another picture.