giveme_bryopsis Posted October 18, 2016 Share Posted October 18, 2016 So I have a (small) decorator crab. Not quite sure what species specifically, nothing terribly unusual. Got it when it was very small, body diameter about nickel sized. Shed once, now a body size of about a quarter. I didn't realize that they could grow that much in 1 shed cycle (other crustaceans don't grow that much). I call that critter Ghillie (looks like it is wearing a Ghillie camo suit). So anyway, very peaceful little critter, despite the scissor claws. Doesn't pince when grabbed (gently), unlike my totally harmless but ferocious defenders, the (non-anemone) porcelain crabs. Runs away from said porcelain crabs when they wave their claws. Anyway, that's the good stuff. Now with a new, larger body, Ghillie is really busy decorating. And that means that my poor softies (anthelias, now also big finger leather and goniopora (!)) are getting mowed over. I keep the anthelias/leather etc for my pygmy file fish, as these beige, striped, pulsing/moving type softies are apparently their favorite hiding/hangout spots. I get it, I brought home a decorator crab. Ghillie does what Ghillie is supposed to do. My question to any fellow deco crab keepers: do they stop cutting up stuff after a few days with their new skeleton or is this a daily, ongoing thing? Also, do the cut-off pieces continue to live/spread about the tank, or are they generally just "cut flowers"? Link to comment Share on other sites More sharing options...
mFrame Posted October 18, 2016 Share Posted October 18, 2016 They will continue to decorate when the lose items, much like urchins that carry things around. Depending on the coral, but yes, the cut off pieces they drop will usually colonize other parts of the tank. I've seen this done with anthelia, gsp, xenia, mushrooms. You'll want to either make sure you don't have anything in your tank that you only want in a specific area or rehome him to a tank that you don't mind him playing Johnny Appleseed in. Link to comment Share on other sites More sharing options...
giveme_bryopsis Posted October 18, 2016 Author Share Posted October 18, 2016 Thank you. I suspected that they continue to decorate (would get boring otherwise). I don't mind stuff spreading one bit, I just don't want everything cut off and dead. I will continue to monitor and make a decision to remove if this gets to be too much cutting on the softies (they don't grow that fast). I like Ghillie, fun to watch and play "where's Ghillie?" - I usually find it be looking for a spot of polyps that doesn't belong. Ghillie can have all the (macro) algae around, but don't be a (reef) goat Link to comment Share on other sites More sharing options...
Sascha D. Posted October 18, 2016 Share Posted October 18, 2016 I had a gorilla decorator crab in 1999. That growth doesn't sound very far off to me. I would expect them to double or triple in the first year. It would continually decorate it's shell with stuff from around the tank. The shell wasn't drastically different from day to day but I could tell that some things were replaced. When it molted the shell would remain decorated and it would start over. It usually molted in a cave and the corals it was carrying recovered if I found them. Leathers and Xenia are pretty tough. They will wilt while being transported, but they should survive if they fall off in a lighted area. I would be concerned about that sps coral though. Link to comment Share on other sites More sharing options...
giveme_bryopsis Posted October 18, 2016 Author Share Posted October 18, 2016 I had a gorilla decorator crab in 1999. That growth doesn't sound very far off to me. I would expect them to double or triple in the first year. It would continually decorate it's shell with stuff from around the tank. The shell wasn't drastically different from day to day but I could tell that some things were replaced. When it molted the shell would remain decorated and it would start over. It usually molted in a cave and the corals it was carrying recovered if I found them. Leathers and Xenia are pretty tough. They will wilt while being transported, but they should survive if they fall off in a lighted area. I would be concerned about that sps coral though. I didn't realize they grew that quickly. Not any kind of gorilla crab, claws are very fine scissors/cutters, no crushing power whatsoever. From the damage to the gonio, it looks like Ghillie very surgically removed polyps from the skeleton, not just snip them in half. I might have to rehome the gonio, as it retracts when the file fish get too close and it is more delicate than leather/xenia/etc. Thanks for your info, appreciate it! Link to comment Share on other sites More sharing options...
Sascha D. Posted October 18, 2016 Share Posted October 18, 2016 I estimate my inverts molt every 30-45 days until they're close to adult size. If you're dosing iodine then that may cause them to molt more often. They'll also grow faster the more nutrient rich the environment is. Link to comment Share on other sites More sharing options...
giveme_bryopsis Posted October 18, 2016 Author Share Posted October 18, 2016 I estimate my inverts molt every 30-45 days until they're close to adult size. If you're dosing iodine then that may cause them to molt more often. They'll also grow faster the more nutrient rich the environment is. Both my freshwater fan shrimps and SW porcelain crabs molt well, but they grow only a little bit with each molt (normal estimates seem to be 10-15% growth per molt). This little one at least trippled in body volume, if not more, in just 1 molt. Yup, they all get iodine supplements and seem well fed. Link to comment Share on other sites More sharing options...
Sascha D. Posted October 18, 2016 Share Posted October 18, 2016 I've never had porcelain crabs, but my book says they have a max size of 1". Decorator and Sally's get up to 3-4" and Emerald Crabs are slightly smaller at 2.5-3". The faster growth rate could be because of the larger adult size. I put a cleaner shrimp in every one of my tanks and they always max out within 18 months. I haven't had a sally since 2002 and I don't remember much about them. Link to comment Share on other sites More sharing options...
giveme_bryopsis Posted October 18, 2016 Author Share Posted October 18, 2016 I've never had porcelain crabs, but my book says they have a max size of 1". Decorator and Sally's get up to 3-4" and Emerald Crabs are slightly smaller at 2.5-3". The faster growth rate could be because of the larger adult size. I put a cleaner shrimp in every one of my tanks and they always max out within 18 months. I haven't had a sally since 2002 and I don't remember much about them. excellent point! my freshwater fan shrimps are large 2-5+ inches, but they are also very long lived (more than a decade to grow that large). So, assuming larger adult size and not extremely long life span, that incredible growth rate makes sense. I still have a hard time believing that it could grow such a much larger skeleton inside the little one, but that's what "pumping it up" once the old skin is gone is good for. so much neat stuff to experience with all these creatures. Link to comment Share on other sites More sharing options...
giveme_bryopsis Posted October 20, 2016 Author Share Posted October 20, 2016 to close this out - for now, the decorator crab is staying. He's always working on his ghillie suit indeed, but is just too entertaining to remove. I will instead remove the poor goniopora from the tank; everything else is not being attacked badly enough to be endandered. Thanks everyone for your experiences and info. PS - Ghillie is now easy to spot under blue lights (nights) - the gonio polyps glow Link to comment Share on other sites More sharing options...
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