Emerald crab picking at frogspawn?

[flatlandreefer]

I have seen one of my two emerald crabs sitting on top of my frogspawn seemingly picking at something on the top of the head. Can emeralds do real damage to a frog spawn and actually eat it? Is this concerning if it happens occasionally?

[Superdave]

I keep an emerald crab as a preventative for the green hair algae.  Mine end up dying for some reason, so I am trying to feed this one more.  I was told they can get very aggressive (if they are hungry and or not) so I would not be the least bit surprised.  The one I have "grazes in the GSP forest" and while it seems to pick, does not do any real damage.  

 

In general, there is a wide range of experiences with crabs.  Some can be aggressive or the perfect companion in a tank full of softies and get along just fine, regardless of the "disposition" we expect.  

 

If I was you and had any doubt, I would remove it and just try another one if that is the type of crab you want.  No reason to stress about it.  

[GregEmmitte]

I've seen them eat Kenya trees

[Nart]

From my personal experience of keeping emerald crab...

When they are well fed they are fine. I witnessed my emerald crab, shortly after feeding it and my corals. It decided it wanted seconds and walked over to my acan and started picking at it. I said "oh, no harm done". Two seconds later... he rips the flesh off my acan and started eating it. I screamed out in my living room "NOOOOOOOOOOOOOOOO!!!!!" (my acan has been through a lot for it to get to where it is now lol)

 

I decided to remove him and give it back to my LFS... well, I couldn't catch the sucker. Guess what? two days later, the emerald crab decided to venture down near my pistol shrimp's hole. I heard a pop-pop-pop-pop. Walked over... and the emerald crab is dead. Kind of sad, but my pistol shrimp must've known how I felt about the acan lol.

[Clown79]

We never know how things may work out with any livestock we add.

 

Most emeralds will pick at corals but they are just cleaning it but theres no guarantee

 

I had peppermint shrimp do the same thing.

Tore 2 acans and a favia apart. 

[Kellie in CA]

I've been lucky with mine so far.  He definitely picks at the corals, but I think he is just cleaning up all the algae around them. Usually the next day they look happier and open up bigger, especially the zoas. 

[gulfsurfer101]

 When in doubt toss it out! The way you bait a crab is to put a glass cup in your tank near his spot then bait it with a piece of shrimp. He'll be able to get in but not out!

[LX20000]

2 hours ago, gulfsurfer101 said:

 When in doubt toss it out! The way you bait a crab is to put a glass cup in your tank near his spot then bait it with a piece of shrimp. He'll be able to get in but not out!

He walks in the cup, eats the shrimp, walks out of the cup. I don't get it....

 

[gulfsurfer101]

1 minute ago, LX20000 said:

He walks in the cup, eats the shrimp, walks out of the cup. I don't get it....

 

No your not getting it! He is able to climb into the cup but not climb out. Just remember to lean it against the rocks he likes to camp out in so he can get in there easily. Try baiting directly after lights out for best results. 

[gulfsurfer101]

If he can escape the small cup then try a bigger glass. 

[samnaz]

Do you feed it anything? Or does it rely solely on algae in your tank? Maybe there isn't enough to keep it full and satisfied.