ReefCleaners micro decorator crab info thread

[Tired]

I don't have a plastic ruler that's not also a hole punch (and therefore very bulky), so here's some size comparison pics with a clean dime. I wouldn't leave a dime in the tank, but I can't imagine saltwater being corrosive enough that a dime will leach anything into the tank in 30 seconds. For folks who don't live in the US, a dime is 18mm across. 

Water magnifies things pretty considerably. I genuinely thought he would be bigger compared to the coin, from how he looks. Nope! He's still pretty small. 

[A.m.P]

You gunna' eat that dime?

[Tired]

He tried! Then he evidently realized it wasn't food, and walked away to sulk about it. 

 

Also, assuming these can be sexed the same way as other crabs, this is definitely a male. I had a look at the empty shell. 

[Tired]

 

....that frag is supposed to have 4 polyps on it. 

 

Sir, please do not snip my zoanthids to wear. Sir. Those aren't even the small ones, those are a medium-sized polyp. 

 

So, yeah, these will apparently wear zoanthids. Hopefully it only wanted a couple and won't go bother something else. We'll see if the ones on its back survive- they do not appear to have been very neatly fragged, there are kinda some stubs left. Normally I might think the stubs could grow into new polyps, but I have amphipods that swarm anything that's remotely upset, so they'll probably be devoured. Least I have one healthy one, possibly two? They keep getting walked on and annoyed into closing again, so it's hard to check. 

 

I'm still keeping these. They're cool. But apparently I should try to avoid frags with just a couple polyps, and/or put those up out of reach. Maybe I can temporarily glue little frags to the back of the tank until they get a bit bigger? Decorator crabs can't climb smooth surfaces. 

[billygoat]

The stubs are likely to regrow at least? Zoanthids are damn hard to kill. But still, I can see that being pretty annoying... although if it happened in my tank I wouldn't be too upset. I've got zoanthids coming out of my ears these days. 🙄

 

These little crabs are pretty dang cool. I'm thinking of getting a few more now that the Maw is no longer around to eat them.

[Tired]

Yeah, I think if the amphipods don't chew the stubs into nothing, they'll regrow. At least it was the no-name (but pretty) zoa I have several of, and not one of my couple named frags that have one polyp and a bud. 

This is them before being rudely fragged. There's now one intact polyp, one that I think he got some frill off of, and a baby polyp that looks intact.

If he does this again, I hope I can at least film it. I'd let him, if it was one of the things I have extra polyps of, to see what happens. Must have taken some effort, though! These guys are decently thick, his little claws look too small to get them off. 

 

I do suggest getting some, if you can. Though I'll tell you that they're now under the same listing as the mime crabs on ReefCleaners, as in the listing is for either/or. I'm not sure why. You might want to email ahead and ask if they have any decorator crabs, and if they could send specifically those. Or, I know they sell regular-sized decorator crabs, you could always just try one of those. Since everything wear-able in your tank is either an excess of zoanthids, or a macro that could handle being fragged. 

I've gotten two mime crabs from RC, also. One has a shell the size of a split pea, and I'm pretty sure by the fact it came in with eggs that it's a full-grown adult. I've seen it once since adding it. I don't know its name. The other is a heart mime crab, carapace maybe 1/4" across? And I've actually seen it a few times, wandering around, but it would probably vanish in a non-pico. It lives under an overhang by my hair-algae-covered fire fern and grabs with remarkable vigor at any food I put near it. That one might grow bigger, I'm not sure. 

 

These guys are, I'm very sure, not remotely predatory. They're bad at catching frozen mysis, for crying out loud. I have to deliberately feed them with tweezers, because if I squirt a mysis shrimp at them, they can't reliably catch it. My trimma goby briefly sat on one with no problems. I can't imagine they could threaten anything mobile, short of, maybe, a very small dying fish. Or a particularly stupid amphipod. I saw a video where a decorator crab caught and ate an amphipod that landed on its back, but I can't really picture mine doing that. 

[Tired]

Those zoas, shockingly, didn't survive. Didn't even open up. I don't know if the crab removed them, or if the amphipods ate them. Crab hasn't touched zoas yet, so it looks like these might experiment with zoas, find it unsatisfactory, and stop there? Which is good. 

 

Oh, and someone got excited during feeding time, somehow climbed onto a nerite snail, and gave me a good opportunity to measure. 

Still a pretty small crab. This one's a male, if the usual method of sexing crabs (shape of the tail) works on these. The detritus on the belly seems to be intentional, it won't blow off. 

[growsomething]

I finally saw one.  Spotted a tiny waving claw under a rock while feeding our baby, and peered underneath.  He quickly hid.

[Tired]

If yours are hiding constantly, and you don't see them out, about, and covered in algae, you probably got mime crabs. Micro decorators, since they're camouflaged, go outside. Are the shells on yours the size of half a pea or so? Look like this? 

[growsomething]

Something like that.  There were no decorations on the part I could see, so must be mimes

[Tired]

Mime crabs are pretty cool, but some of 'em are just too tiny. I like my heart mime crab, not that I'd recommend it for anything larger than a pico. Those little spotty ones, though? Mine came in with eggs, and I'm pretty sure crabs don't carry eggs until they're mature adults, so they apparently don't grow bigger. I've seen mine twice, both when I was moving the algae it lives in. 

[Tired]

Tried on some fine macro a few days ago. Just on the one leg, for some reason. Doesn't seem to be wearing it today, might have eaten it. Lil guy eats bits of macroalgae now and then- not enough to do any real damage to a clump of it, though. He just eats bits he finds loose. Fair enough!

[growsomething]

He's so camouflaged  I can hardly make him out. 

Wish my emerald was like that.  I had some cool algae popping up on my live rock (mermaid's fan, etc) but also bubble algae, ergo the emerald and no macro.  If I take him back to the lfs I wonder if the mime crabs would take care of any bubble algae...or if it will come back at all.  He's kept the tank denuded for 6 months now.

[Tired]

I don't think the mime crabs will take care of basically anything. They seem purely decorative. They're so small! 

 

You can try careful manual removal of the bubble algae, instead of an emerald crab. Or it might not come back. Some strains of it aren't terribly vigorous. 

[Tired]

At this point, I'm pretty confident declaring these safe for other animals. The only conflict I've seen is that sometimes the decorator crab mistakes the porcelain crab's waving "go away" claws for something interesting, and goes towards the porcelain to check it out. The porcelain does not appreciate this. That, and sometimes the hermit crabs will stand on the decorator, apparently mistaking it for a rock, and annoy it by eating its costume. I've seen my trimma goby sit on the decorator without any aggression showing up, and when the decorator has approached the goby, it's been in a relatively calm and investigative manner. 

 

All in all, I'd say a crab that may occasionally annoy small livestock by checking out what it is, but won't hurt anything else, is a pretty reef-safe crab. I feed it a bit of mysis every few days. Haven't had any more zoa-snipping incidents, and the zoas that got snipped grew back from the leftover stubs. I think the lil guy just decided that zoas are no good to wear. 

[Tired]

At least somebody involved with this tank likes cyano. 

[CD_Scapes]

49 minutes ago, Tired said:

At least somebody involved with this tank likes cyano. 

Is john no longer a sponsor? I can't find his reef cleaners threads

[Tired]

https://www.nano-reef.com/forums/forum/73-reef-cleaners/ 

Looks like it's still here for me.