I have 4 species of snails and a spotted porcelain crab in a 10 gallon Coral/Invert Quarantine tank (Fiji AIO cube). There are currently no corals in the QT tank. I have had livestock in this tank for 6 weeks preparing them for introduction to a new Red Sea Reefer 200XL display.
I powered off the main pump today in the Invert QT while feeding pellets and when my plastic bio balls floated to the surface of the sump area they were accompanied by a crab's exoskeleton! I was quite surprised to see this as my spotted porcelain crab in the display area clearly had his shell. Was this possibly left over from a weeks earlier molt that found its way into the sump? Seemed very unlikely since the shell looked quite fresh and was mostly intact.
I tried to retrieve the shell but it sank on me in the small confined chamber. After extracting all of the bio balls I was still unable to retrieve it. I then decided to abandon it and when I turned my pump back on - LO AND BEHOLD - a freshly molted crab came to the top of the second chamber of my sump area and became stuck on the overflow.
I was quite excited! 6 weeks previous I had purchased two new spotted porcelain crabs and after the first week one of them lost both his claws and then disappeared a few days later. I assumed that he had died and been consumed by his crab-mate, the shrimp, and possibly snails. Never found any remains except for the two claws (that he had lost) in the sand. Fortunately, I was wrong. He had escaped to the depths of the sump where for the past 5 weeks he was happily living in seclusion in a tray housing matrix media. (Makes me wonder too if this might be where one of my decorator shrimp went ... will have to take closer look next water change.)
In my excitement (and because I'm a total rookie and was unaware that you should not disturb a molting invertebrate) I scooped him into the main display as quickly as I could. Porcelain Crab recovered! This is great! Back from the dead! ... Not so fast! The little guy was caught in the main flow jet ... propelled across the display and reached out and grabbed hold of an Astraea snail perched on the glass. (It made me think of the dentist office scene in Finding Nemo.) As I watched him flailing vigorously in the current I was amazed at his ability to hold on ... but I decided he needed a better place to rest ... after all the poor guy had no skeleton ... and I carefully moved him down to the sand bed. Within a minute several Nassarius Vibex snails were on the move. I didn't quite realize yet that they were heading for the crab. Those Vibex can seriously move across a sand bed ... incredible how gracefully fast they are. They promptly attached themselves to the freshly molted crab. I'm pretty used to watching my snails (and shrimp) provide courtesy cleanings for one another ... but it only took my inexperienced brain a few seconds to realize that this is not what was happening here. My poor crab was completely unprotected.
I quickly knocked the snails from the crab and scooped him into a net. He wasn't moving at all for at least 20 minutes. I thought that I (and the snails) had done him in ... but fortunately in the last hour or so I have seen him slowly moving. I now have him in a medium flow area and have left him isolated in the net. I'm hoping for a successful molt and full recovery. Notice in the photo below how one of the Vibex is still trying to get to him.
I just finished researching invert molting and am quite amazed about the process. Click here for a great summary.
But I have a few questions on what happened here and am looking to increase the chances of this guy's survival:
Any help on these questions are appreciated. Thanks in advance!
I powered off the main pump today in the Invert QT while feeding pellets and when my plastic bio balls floated to the surface of the sump area they were accompanied by a crab's exoskeleton! I was quite surprised to see this as my spotted porcelain crab in the display area clearly had his shell. Was this possibly left over from a weeks earlier molt that found its way into the sump? Seemed very unlikely since the shell looked quite fresh and was mostly intact.
I tried to retrieve the shell but it sank on me in the small confined chamber. After extracting all of the bio balls I was still unable to retrieve it. I then decided to abandon it and when I turned my pump back on - LO AND BEHOLD - a freshly molted crab came to the top of the second chamber of my sump area and became stuck on the overflow.
I was quite excited! 6 weeks previous I had purchased two new spotted porcelain crabs and after the first week one of them lost both his claws and then disappeared a few days later. I assumed that he had died and been consumed by his crab-mate, the shrimp, and possibly snails. Never found any remains except for the two claws (that he had lost) in the sand. Fortunately, I was wrong. He had escaped to the depths of the sump where for the past 5 weeks he was happily living in seclusion in a tray housing matrix media. (Makes me wonder too if this might be where one of my decorator shrimp went ... will have to take closer look next water change.)
In my excitement (and because I'm a total rookie and was unaware that you should not disturb a molting invertebrate) I scooped him into the main display as quickly as I could. Porcelain Crab recovered! This is great! Back from the dead! ... Not so fast! The little guy was caught in the main flow jet ... propelled across the display and reached out and grabbed hold of an Astraea snail perched on the glass. (It made me think of the dentist office scene in Finding Nemo.) As I watched him flailing vigorously in the current I was amazed at his ability to hold on ... but I decided he needed a better place to rest ... after all the poor guy had no skeleton ... and I carefully moved him down to the sand bed. Within a minute several Nassarius Vibex snails were on the move. I didn't quite realize yet that they were heading for the crab. Those Vibex can seriously move across a sand bed ... incredible how gracefully fast they are. They promptly attached themselves to the freshly molted crab. I'm pretty used to watching my snails (and shrimp) provide courtesy cleanings for one another ... but it only took my inexperienced brain a few seconds to realize that this is not what was happening here. My poor crab was completely unprotected.
I quickly knocked the snails from the crab and scooped him into a net. He wasn't moving at all for at least 20 minutes. I thought that I (and the snails) had done him in ... but fortunately in the last hour or so I have seen him slowly moving. I now have him in a medium flow area and have left him isolated in the net. I'm hoping for a successful molt and full recovery. Notice in the photo below how one of the Vibex is still trying to get to him.
I just finished researching invert molting and am quite amazed about the process. Click here for a great summary.
But I have a few questions on what happened here and am looking to increase the chances of this guy's survival:
1. Nassarius Vibex or Whelk?
I discovered that predatory Whelks look similar to Nassarius ... so it crossed my mind that maybe I have Whelks? But I purchased from a reputable invert supplier and based on looking at some online resources they really appear to be Nassarius Vibex. (Maybe an expert can confirm by the photo above.) So assuming that indeed I have Nassarius ... is this a sign that they are really hungry? This is a newly cycled quarantine tank and I periodically (every 4-5 days) feed the tank a couple pinches of Spectrum high density sinking pellets for the crabs and shrimp ... but possibly I might need to feed more? I also read that a newly molted invert gives off quite a scent ... so possibly the Nassarius are just responding to that?2. Need to eat their shell?
I read that after molting that the crab will consume a portion of its exoskeleton to increase Calcium to prepare for the rapid growth of the new shell. I went back a second time to attempt to recover the shell from the sump area to place it with him as a dining option but the shell was in a very hard place to get and it broke up into small pieces. I was unable to retrieve it. My tank is currently at 440 ppm Ca (near my target of 450 ppm). Is there possibly enough Ca available in the environment for a normal molt? Is there anything else that I can do to help since I separated him from his shell? Possibly it will just take longer to regrow new armor?3. Safe Release?
I was caught off guard and don't have a small breeding sub-tank to isolate him from the rest of the tank. I'm going to pick one up to have on hand for similar emergency situations in the future. Also, I realize that even though this is a quarantine tank I likely need some more hiding locations so they do not seek out the hypogeum for safety. I probably have kept them a little too much in the open. For now I plan to leave him isolated in the net until he grows back his shell. I placed a few pellets in there as well but he has paid no attention to them as of yet. I read that they are not very active and do not eat during this phase. How long should I keep him isolated in this manner? Will it be obvious when he has his new shell and ready to get back to the display? I intuitively want to keep stress low and don't want to keep him feeling exposed longer than I have to. Should I provide some additional places for him to hide in the net so he feels like he is protected?Any help on these questions are appreciated. Thanks in advance!
