Sally Light Foot

[Jace]

I've been trying to do some research on theise crab's and would like some more information on them..Any information Good/bad Wanted Thanks,

[yellow tang]

I have heard that when big they are not reef safe and they are distructive they will also kill fish but these is just what two books told me.

[capman]

Sally lightfoot crabs are delightful animals.

In fact, all crustaceans are delightful animals. You really can't get much cooler than a shrimp or crab or lobster. They are intricate and sophisticated creatures, and they are smart and alert and interactive.

Pretty much all crabs (except maybe porcelain crabs?) are opportunistic feeders though. Individual species have various specialized adaptations (e.g. emerald crabs are adapted for eating algae, and sally lightfoots do a lot of that too it seems), but even species that tend to be herbivores will not hesitate to eat animals that present themselves. I would not keep any crab like this with fish small enough to be overpowered by the crab if the crab grabs it. I don't know for certain what would happen if you kept them with the likes of coral banded shrimp, peppermint shrimp, or cleaner shrimp, but I'd bet the shrimp would be in big danger too - if they did not get caught otherwise, I think there would be a very good chance of them getting caught and eaten just after molting. (NOTE: I have not actually seen sally lightfoots catch any of these animals - I have been careful about who I keep them with - but I have seen them lunge at and try to grab animals that swim by).

I doubt that sally lightfoots would eat corals (just a guess), but I would not be surprised if they would steal food from large polyps, possibly damaging the polyps in the process (just a guess for this too).

On the other hand, sally lightfoots (and other crabs) can be vulnerable when they molt - I once had one get eaten by a green brittle star just after it molted, presumably before its exoskeleton hardened up and it regained full functionality/mobility. Crabs can be vulnerable to being eaten by other crabs when they molt as well (though female crabs and shrimp can only mate right after they molt, before their exoskeletons harden up).

If you have a tank with large-ish fish that are not going to be a threat to a crab (e.g. tangs and such) and that are large enough to not be harmed by a crab like this, I'd say go for it. But the crabs do grow, and fairly rapidly at that, and they will be much more of a threat to things when they get bigger.

These crabs are nothing though compared to swimming crabs (the group of crabs that blue crabs belong to - I have kept a small species of swimming crab that I got from Gulf Specimens in Florida, which sells to schools and institutions only, unfortunately)....these are some of my absolutely most favorite animals in an aquarium, but they have much larger claws than sally lightfoots, can swim pretty fast (sally lightfoots don't swim really), and are definitely predaceous. A crab like this needs a tank to itself (though they can live with the likes of sea stars, urchins, etc, and they would probably be fine with smaller polyped corals, and the ones I had did not bother smaller feather duster worms).

Here is a photo I found on the Web of Portunus gibbessii, which I think is the swimming crab species I used to have in the lab (this is a smaller relative of the blue crabs that people eat - maximum width of the body on my biggest one was maybe 3" or so, or maybe a bit more):
http://jamarc.fra.affrc.go.jp/zukan/c/c-1/c-m034/c-146.jpg
These are super super cool animals, that will watch you when you walk into the room and beg for food the way fish do, and they would swim up and grab food from my fingers (a really stupid thing for me to do with larger crabs!). Unfortunately, I've not seen these for sale in the aquarium trade.

[RJREEFER]

Ok, I don't have as much info to post as Capman, but I can tell you that I have a Sally Lightfoot in my 75G reef. She is coupled with other inverts such as 2 Emerald Crabs, Skunk Cleaner Shrimp, Coral Banded Shrimp, Small Hermits... Everyone seems to do just fine. I only ever see Sally munching on algae, never anything meaty. Seems to keep to herself, likes the back of the tank and molts a lot (so she must be a fast grower). Based on information I have read, she might come out of the reef one day but for now, seems to be a reef happy little critter. I don't ever see her bothering corals either :)

[tjp]

I have 2 of them in my 120g and I don't see it as a problem, I see them running around picking at the live rock for food. I think that they are a good part of a good clean up crew.
I've kept 1 before for over 3 years and the 2 I have now for about a half a year and I do have other shrimp in the same tank.
I'd say get 1, they are fun to watch.

[capman]

This is cool to hear of these crabs getting along fine with shrimp. I still think it is a risk (I don't trust crabs with any animal that they can potentially overpower), but maybe not as big of a risk as I had thought. Also, I suspect the larger the tank the lower the risk to things like shrimp.

[capman]

.... I only ever see Sally munching on algae, never anything meaty. ....

Mine graze on algae mostly, but also eat mysis shrimp and other such foods when I feed the tank those sorts of things.

[Jace]

just the information I wanted, any input on any other Crab's I think I know the basics about Emerald's I'm looking for somthing on the smaller side which is why I asked about the Sally light foot's because I was at a LFS I do not certainly trust and they said that this sally light foot was a messed up gene and super rare that it was so big it was about the size of a emerald crab with longer leg's.. I'm looking to go pretty heavy on the inverts in my 10g nano sense It will be fishless. Everything reefsafe please..

[capman]

Sally lightfoots, of various species, are quite common animals in the wild. They are not rare at all. Without searching very hard, I have encountered them in shallow waters not far from shore in the Florida Keys, for example. Mithrax sculptus ("emerald crabs" can be easily found in those same areas (and other species of Mithrax that get MUCH larger can be found on the reef).

The sally lightfoots sold for reef tanks don't get huge, as I understand it, but they get a lot bigger than the sizes they usually are when initially sold. My recollection is that the largest ones I've had, after they grew a bit, have been larger (though not necessarily more massive) than the largest emerald crabs.

Personally, I would not hesitate keeping these crabs in a fishless tank with just corals (though there is always potential for food stealing from polyps with crabs, or even cleaner shrimp, for that matter).

[David Grigor]

Like most things in the hobby. Sally Lightfoot crabs are generally reef safe but not a guarantee. I've have more that were just fine than I have that misbehave but success rate is not 100%.

It's been many years ( and I'm too lazy to look it up ) but there was a generality that it was either the male or the female that had better success rate with. But I just can't seem to recall which of the two it was and not convinced it was totally accurate. How's that for a non-answer......

[Steve Whited]

i have personaly seen a sally light foot in a reef mix that was 4 inches from tip of the leg to tip of the leg and they had no problems with them

[capman]

As an aside....

For multiple reasons, I'd suggest you avoid this Galapagos species of sally lightfoot in your reef tanks...

http://www.earthshots.org/photos/533.jpg

http://carsonstravels.us/Galapagos%20Pictures/crabs/sally%20crab%20and%20iguanas%20full.jpg

Probably ought to avoid those iguanas too....they do graze on marine algae underwater, but they'd probably knock over some of your corals!

http://www.jaybeestock.com/StockEcuador/Galapagos2.jpg

And these penguins would probably not only knock over your corals, but eat your fish too! Not to mention the bigtime nutrients they'd add to your tank. Definitely not reef safe!

[redeclipse6049]

As an aside....

For multiple reasons, I'd suggest you avoid this Galapagos species of sally lightfoot in your reef tanks...

http://www.earthshots.org/photos/533.jpg

http://carsonstravels.us/Galapagos%20Pictures/crabs/sally%20crab%20and%20iguanas%20full.jpg

Probably ought to avoid those iguanas too....they do graze on marine algae underwater, but they'd probably knock over some of your corals!

http://www.jaybeestock.com/StockEcuador/Galapagos2.jpg

And these penguins would probably not only knock over your corals, but eat your fish too! Not to mention the bigtime nutrients they'd add to your tank. Definitely not reef safe!

Those things look awesome!

[capman]

I'm so glad someone appreciated my silly post. I was beginning to wonder whether it would get any response at all (and that was making me sad ;) ).

Yes, those crabs are cool. I've never see them in person. Until about 10 or 15 years ago or so I used to think that those were the only kind of sally lightfoot crabs that there were. I had no idea there were other kinds, and was pleasantly surprised when I learned that there were others.

Actually though, as I read a bit more about these crabs - the Galapagos ones, as well as the ones we keep in our aquaria - it looks like these two crabs are not as closely related as their shared common name might suggest. It seems that they are in different families. Interesting.

And this Wikipedia page tells some more interesting stuff (assuming it is true....I've seen some crazy stuff on Wikipedia pages, but I suspect this page is pretty accurate): http://en.wikipedia.org/wiki/Percnon_gibbesi

It looks like our common aquarium sally lightfoot crab is very widespread in the wild, and has even become an invasive species in the Mediterranean.

[capman]

By the way, have any of you ever seen the Far Side cartoon in which Darwin has just arrived at the Galapagos Islands, looks at the shore (from the ship he is on), and says "Whoa, crab city!" ? That was always one of my favorites.

[redeclipse6049]

hah, I don't think i've seen that one.

One of those diving iguanas would be pretty cool to have though. Do a combination terrarium/ reef tank so it could jump in and munch on your rocks when it felt like it... haha

[capman]

Oops, I think my memory of that Far Side cartoon was wrong. Darwin's comment (standing on the deck of the ship, looking out at the lava rocks along the shore covered with those marine iguanas) was "Whoa, lizard city!", and the caption at the bottom of the cartoon was something along the lines of "Darwin's arrival at the Galapagos Islands". (It is much funnier if you actually see the cartoon though, of course).

Same idea, but somehow sounds funnier with lizard rather than crab, I think.

[redeclipse6049]

haha, it sounds more familiar now that you say lizard though...