Actaeodes tomentosus (Mud Crab)

Source Reeflex.net

QUICK STATS

• Care Level: Very Easy
  
• Temperament:
  
• Reef Compatible:
  
• Water Conditions:
  
• Max. Size:
  
• Color Form:
  
• Diet:
  
• Origin:
  
• Family:
  
• Insert Date: 8 March 2011
  

This crab was known as Paractea Monodi. It lives on coral reefs in the tidal zone. They often ship with life rock. Most crabs are getting disposed of because of fear that they eat fish or corals. It does seem some crabs can eat fish but most prefer algae.

Tuesday I picked up two crabs from Sjaantje in trade for couple of Kenya Trees. She had no idea what kind they where.

First suggestion was a Actaeodes tomentosus or Paractea monodi (old name?). It does look a bit like the one I have, except for the redish eyes? An article on this crab on reeflex.net.
One that I found is a family of the other crab I got and is called the Xantho poressa. Here is a piece I found about this crab on wikipedia.

We are keeping this one as the Actaeodes tomentosus or Mud Crab. I saw pictures of someone who has such a crab and it looked very much like the one I have.

Yesterday I completed the fragtank and dedicated half of it to animals like the Mud Crab. So I caught him out of the sump yesterday and placed him in the fragtank. He didn't seem to like it a lot, but hopefully that will change in time.



Here is a movie I made later of him feeding.

Bought 4 new hermit crabs yesterday, 3 black ones and a orange one like I bought the day before. One black and the Orange one moved into the Red Sea Max, another black one moved into the frag/crab tank and the last one moved into the sump.

The hermit that moved into the frag/crab tank already had a hard time. The small red hermit I got the day before has no problems with this crab, but the new one got harassed right away. And also with the introduction of the second crab he immidiatly got bullied this morning. I now placed a frozen fish in it that I normally feed to the anemone, hopefully the crabs will take that for dinner instead of my little hermit.


Here is a movie of the crab with the hermit.

Currently I have two members of the Xanthidae family located in my little crab aquarium, and I have been observing them and finding information about these “unwanted” creatures.

The Xanthidae family is one of the biggest crab families, it is divided in 13 sub families containing over 500 different species. These species are poisonous to eat since their toxins can’t be destroyed by heating/cooking. The Toxins come from bacteria living in symbioses with the crab, both from the Vibrio genus. There is no antidote for these toxins either and they will cause Paralytic Shellfish Poisoning. But on the other hand, they are not venomous, so they have no way to introduce their toxins by stinging or biting. Some species however do have hairs on them that can cause allergic reactions.

They can become anywhere between 5 and 10 centimetres and some of them are beautifully coloured. They move slowly and hide most of the times. Most of them are opportunistic feeders, the ones I have don’t bother much with any other invertebrates around them but do eat frozen shrimp and fish when provided. They once went for a smaller hermit crab but gave up when they noticed it was too much trouble. I do think they would go for fish or invertebrates that are alive but weakened.

In most aquariums species for this family are no threat. They could be a threat when you have animals that could feed on them, since I haven’t found any information on the effects of the toxins on other animals.
According to some websites they are not reef safe, but the only non-reef safe thing I noticed so far is that they enlarge their hiding spaces, making holes in life rock. This will of course weaken the rock making your reef weak with the risk of collapsing.

The two species I’m testing with are the very common Actaeodes tomentosus and the less common, but very nice looking Lophozozymus edwardsi. Both of them behave in the same way as far as I can tell so far and both fit in the description given above. Both live together with 2 smaller hermit crabs, 2 smaller turbo snails, a Babylon sand snail and a horseshoe crab. Only saw them take a swing at one of the hermits when it ran into them. Both are about 4 or 5 centimetres now, so actually rather big.

This time I used the light on my phone. Also the moonlight was already off around this time.

He managed to get to the frag part of the aquarium, also there he moved underneath a rock on the first plateau and was able to move it across the plateau. I got him out and placed him back. Hopefully he stays there now.