LFS Wisdom

[Searchlights]

So I go to my lfs today to grab my first clean up crew. I'm on a tight budget until payday so I just picked up a handful of blue legged hermits and some snails to clean up some diatoms that I have from the tank being newly cycled. As I'm looking around, I ask the owner if he had any recommendations for any other invert that would help with any algae problems in the future. He told me that the Sally Lightfoot crab would be really good as a general scavenger/algae eater (he only had one left.). So I picked one up..... I know I should've done my own research and looked into everything before buying anything, but I trusted the guy because he was the owner of a successful saltwater fish store. Now after I've done a bunch of reading, it seems this crab is a bloodthirsty fish murderer that ambushes poor little creatures and drags them to some horrible crab dungeon in the rocks lol. It is pretty small now though, maybe a nickel sized body. So do you guys think I should keep it? It is dominating algae off of the rocks and sand. It doesn't seem to even care that there is anything else in the tank. I'm just worried that it'll get massive and I won't be able to do anything with it if it causes problems. Any advice?

 

[Betta132]

Sally lightfoots are fast, agile, and good at nabbing things. Sometimes it's possible to keep them with other things, but usually they start causing problems once they grow. I'd suggest removing it before that happens and returning it to the store. Since you only have snails and hermits right now, it's not a huge rush, but I'd suggest getting rid of it before you get any fish that are anywhere near its body size, just in case.
Diatoms and various algaes caused by the cycle will usually fade away once the tank is stable, they don't necessarily need to be controlled. Algae eaters are good, just don't throw more in every time you seen an algae bloom. Keep the water reasonably clean, let the tank stabilize, and it'll pass.
Here's the thing: that guy necessarily didn't get to be successful by giving great advice. He succeeded because he sold a lot of stuff. Sometimes selling a lot of stuff means lying to people- LFS employees/owners aren't always honest. They make more money if they tell you that you can keep something that you may not be able to keep, and they make money if you come to replace fish that have been, say, eaten by a Sally Lightfoot crab.
Now, that's not always the case. Giving good advice does help keep a LFS alive, and it could be that he's only ever seen Sally Lightfoots kept with larger fish. They're okay with big fish. I'd suggest taking the crab back and saying something along the lines of "Hey, I don't really want this crab because I read that they'll kill small fish. Is that true?"
And it's definitely true. It doesn't always happen, but it happens often enough to be a concern. If he says otherwise, he's wrong.

 

[Searchlights]

Well, I tried to take it back today. He wouldn't take it because "their policy won't allow any fish inverts or corals to be returned alive because of the chance of bringing disease into their system." So looks like I'm stuck with the little guy.

 

[Celtic_Fox]

Well, I tried to take it back today. He wouldn't take it because "their policy won't allow any fish inverts or corals to be returned alive because of the chance of bringing disease into their system." So looks like I'm stuck with the little guy.

Maybe he's a candidate for a sump and/or refugium?

 

[hotelbravo]

Rehome on craigs list.

 

[Searchlights]

Maybe he's a candidate for a sump and/or refugium?

Yeah that looks like a good option. I'll probably keep him in the DT for awhile until I buy my first fish and QT it. Then I'll either move him or rehome him. It sucks because I like the way it looks but I can't take any chances.

 

[snorvich]

Maybe he's a candidate for a sump and/or refugium?

The crab or the LFS guy? I would hesitate to listen to further advice from that person.

 

[Searchlights]

The crab or the LFS guy? I would hesitate to listen to further advice from that person.

Yeah he did leave a pretty bad impression on my after that. He said he's never heard of any sally lightfoot ever causing any problems for anyone he's sold one to. But I don't really have a lot of choices when it comes to lfs. I have that one, and a petco in my town. Then I have to drive maybe 30 to 45 minutes to get to another lfs that are all pretty much jerks that are only interested in setting up big custom tanks and selling super exotic 500+ dollar fish. I guess I'll just have to do my research next time and not buy anything that I don't know lol. His livestock and live rock are really good quality though. So it's either that or start ordering online lol.

 

[Coelli]

I have one Sally Lightfoot in my 65g, about 3.5" from toe to toe. It IS scary looking, especially when it moves fast, but to date (my notes say it was added on April 25th) it has not killed or injured anything in my tank - and my fish are small (gobies, a green mandarin, a starry blenny, royal gramma, baby clownfish, etc.). Nor has it harmed any inverts; 6 sexy shrimp, 2 pom pom crabs, 3 acro crabs, etc.). There are two kinds of sally lightfoots btw, one is a shore crab. I think the spider variety maybe has more of a bad reputation than it really deserves.

 

[Calappidae]

Crabs are opportunist. If it's hungry and there is an easy target in front of it, it's gone. Sally light foots are VERY aggressive in comparison to other crabs, because they are fast and can kinda jump somehow, fish don't get away easy.. Making even healthy fish easy targets.

FUN FACT: these crab live near shore and are one of the many primary predators to baby turtles, I can find video of it, but I doubt anybody wants to see turtles ripped to shreds.

That being said, some will have a 1/10 good one, but I think the price of the experiment isn't worth it.

 

[Coelli]

FUN FACT: these crab live near shore and are one of the many primary predators to baby turtles, I can find video of it, but I doubt anybody wants to see turtles ripped to shreds.

Are you talking about grapsus grapsus or percnon gibbesi? The latter is the only one I've seen for sale at LFS, but I have a suspicion that confusion with grapsus grapsus is part of their bad reputation.

 

[Searchlights]

I have the one that looks spider like. Not the bright red one. And he is extremely quick. Like jumping spider quick lol.

 

[Coelli]

I have the one that looks spider like. Not the bright red one. And he is extremely quick. Like jumping spider quick lol.

Yeah, that's percnon gibbesi. I have seen mine jump at my fish, but it's more of a defensive action to scare them away when they get too close, much like when my emeralds wave their claws and rush something. I'm not saying they may not be risky and they never eat anything, just that I don't think they're quite the aggressive murderers people say they are. I actually used to have 3 in the tank but moved two to a different fishless one as CUC. The other two weren't a problem either.

 

[Searchlights]

Yeah, that's percnon gibbesi. I have seen mine jump at my fish, but it's more of a defensive action to scare them away when they get too close, much like when my emeralds wave their claws and rush something. I'm not saying they may not be risky and they never eat anything, just that I don't think they're quite the aggressive murderers people say they are. I actually used to have 3 in the tank but moved two to a different fishless one as CUC. The other two weren't a problem either.

Hmmmmmm, looks like I'll just have to wait and see how it acts. It could be a model citizen for all I know lol. It doesn't seem to bother anything at all. But all I have are snails and blue legs so that doesn't mean much. I guess the future will tell [emoji14]

 

[Betta132]

If everything at the guy's store is healthy and he's not an outright jerk, shop there. Just research everything beforehand, or maybe go ask more questions. Could be he hasn't heard of them doing that. I'd suggest asking what size tank he recommends for various tangs, that's a good test.

 

[Calappidae]

Are you talking about grapsus grapsus or percnon gibbesi? The latter is the only one I've seen for sale at LFS, but I have a suspicion that confusion with grapsus grapsus is part of their bad reputation.

percnon gibbesi. Grapsus I don't believe have contact with turtles at all.

 

[Coelli]

percnon gibbesi. Grapsus I don't believe have contact with turtles at all.

I'm surprised; they are primarily algae eaters and scavengers, one of the reasons they're recommended for reef tanks. They have very tiny claws suited for picking at rocks rather than the huge claws of grapsus grapsus. They also (unlike grapsus grapsus) don't come on to the shore very much.

https://www.researchgate.net/profil...ily_Strait/links/0fcfd4fda4a3f68a5f000000.pdf

"The morphological characteristics of the chela, the feeding adaptations of the gastric mill and the analysis of stomach contents indicate that P. gibbesi is a strictly herbivorous species, a characteristic not shared with any other large-sized infralittoral Mediterranean crab."

 

[Calappidae]

I'm surprised; they are primarily algae eaters and scavengers, one of the reasons they're recommended for reef tanks. They have very tiny claws suited for picking at rocks rather than the huge claws of grapsus grapsus. They also (unlike grapsus grapsus) don't come on to the shore very much.

https://www.researchgate.net/profil...ily_Strait/links/0fcfd4fda4a3f68a5f000000.pdf

"The morphological characteristics of the chela, the feeding adaptations of the gastric mill and the analysis of stomach contents indicate that P. gibbesi is a strictly herbivorous species, a characteristic not shared with any other large-sized infralittoral Mediterranean crab."

Ironically, if you have any openings in your tank they will crawl out. They're something you need a lid for actually.

I don't know how I feel about the "strictly herbivorous" statement. Keep in mind the document you posted was written a long long time ago (1999 I think, I see atleast 50 different dates), so it might not have been a common aquarium pet at that time in which the crab would be more likely observed preying on fish, instead of dedicated lab systems or the wild where they have no reason to go for fish over other algea and dirt. One thing to be careful of is old rumors and statement pre-internet period, since one or two scientist may not see and report what 1m+people see and report.

I did try to look and find the shore turtle attack by Percnon gibbesi, but it was in some movie type nature documentary, and I forget which one. I just seen it a few months ago and reconized the crab instantly. (I think I had mine at the time). Might just be a Percnon but not a gibbesi now that I realize it.

Like I said, crabs are oppertunist, if something is infront of them and they're hungry, they'll take it, but in the wild they're usually never hungry and there is always available alternatives to wasting energy going for live prey. In home aquariums, their food supply is limited so they're more eager to take what they can get.

 

[Searchlights]

Welp here goes the trial run. I just added a pair of SA Fancy White clowns and a really small lawnmower blenny. He's bigger than the blenny but he hasn't bothered it yet. I'll keep an eye out though.

 

[Coelli]

Welp here goes the trial run. I just added a pair of SA Fancy White clowns and a really small lawnmower blenny. He's bigger than the blenny but he hasn't bothered it yet. I'll keep an eye out though.

The Sally Lightfoot was in the tank when my clowns were 1.25" long. I honestly think it'll be fine (though of course I'd hate to be wrong!).