No idea why!

[RusticsReef]

I have this crab in my tank that continuously climbs up the rock work to stick itself in an acro in the exact same spot. I’ve taken him off several times and even moved him to the other end of the tank. Only to find him back the next day. There’s no food or anything out of the ordinary in this small acro. It’s the craziest thing!!! Any ideas? Sorry for the poor quality picture

 

[Uriken]

Interesting. I wrote in the forum about this same activity taking place with a Blue Leg hermit I had climbing to the top of a Digitata. I could remove him and put him on the other side of the tank and the next morning he was back on the top of the same coral. I never could sort out why he was the only one to do this and from what I recall there was no good answer from the forum. I started thinking it had something to do with "new" growth at the tip of the coral and the crab taking a liking to it for whatever reason yet the other crabs never did anything like this to support my thinking. My Digi was healthy and growing BUT over time the crab was irritating it from climbing on it and somewhat shielding it from the light at its tip so I removed him.

 

[anthonygf]

HaHa! Wait till you have up to a dozen climbing your sticks. This same thing happened to me a few years ago. I would remove them and the next day they would be back, but with more of their friends. I got so tired of removing them and finding branches broken off I removed them all. This is why I have snails only, no crabs. You can see where the branches have broken off, on the bright side they did make some decent frags for me! lol

 

[RusticsReef]

The amount of travel this crab has to make to get back to this acro day after day that (unless its eating the acro) has zero food for it makes no sense!! I could see if others were also doing it but why just this one? If it happens again he's going into the refugium.

 

[anthonygf]

The amount of travel this crab has to make to get back to this acro day after day that (unless its eating the acro) has zero food for it makes no sense!! I could see if others were also doing it but why just this one? If it happens again he's going into the refugium.

Makes no sense to me ether. I sure do miss my crabs though.

 

[Uriken]

Makes no sense to me ether. I sure do miss my crabs though.

I have been in the hobby for a good 26 years and I did start to wonder about the current types of Blue Legs being sold. I started to wonder if some of the local fish stores are stocking Blue Legs that may be a bit different than the standard blue leg species that I'm used to being reef safe. I haven't been aware of blue legs eating healthy coral. An it doesn't answer the question as to why in my tank it was just the one particular crab unless from a species type its slightly different? Its always been of interest to solve this being that the crab knowing to move all the way across a tank landscape repetitively and climb onto the tip of that particular coral tells me there is food of some sort that is its motivation. I recall as well this crab getting much larger than what I was used to seeing over the years. It did have blue legs when it was smaller but as it got big it for sure took on legs that were just basic brown.
I'm just throwing out ideas here.