Missing emerald crabs

rjallen

New member
My tank is doing well except I have developed a bad case of bubble algae.
Ordered up 1 foxface- he pecks at it on occasion but he will never make a dent. Its OK as I really like him. At the same time, I ordered 3 emerald crabs.
Placed them into the tank after a long acclimation. One immediately molted and hid. The other 2 started munching right away. After a few days the 3rd crab appeared in his new skin and now much larger. Over the space of a few weeks, I watched the crabs become more secretive but they still were eating BA. I couldn't figure out why the crabs starting hiding as they did not at first [ except for the post molt period above]

For the last 3-4 weeks I have not seen them. I do have a lot of rock in my 120 gallon. But no sign. I have 4 shrimp- skunk cleaner & pepermint, 2 each. I have snails and hermits [ all small]. In addition to the foxface, I have blue chromis [2], small maroon clown, lawnmower blenny, diamond goby, fire fish.

Parameters are Alk-9-10, Ca- 390-410, Mag- 1320-1440, Sp- 1.024- 1.025, Temp.- 77-78.4 f, Ph is a little low- consistently 7.76- 7.9, Zero NH3, NO2, Nitrate NO3 has varied between 32ppm- 8ppm mostly in 10-12 range. Do weekly 10%-15% water changes. TDS water 0- all water is RODI base. Phosphate 0-0.02ppm- run GFI.

Ph reading showed solid 8.0-8.1 with a Salifert test kit, however, I just installed a Apex controller with a lab grade Ph probe and have been getting the lower above readings.

I have had good growth on all fish, snails, shrimp and hermit crabs. All the shrimp have molted at least 1 or 2 times. I have a couple of LPS and a Zoa Colony. One GTB anemone. All doing well

I think the crabs were done by one of their tank mates. Any ideas? The tank has been very peaceful. The worst violence has been the blenny has occasionally picked up a hermit crab and flung it down on the sand. I wonder if he saw the emeralds as competitors?

Has anyone had issues with their emerald crabs being killed? Do yoiu suspect any of my above fish?

The B. Algae is quite bad and I want to replace these crabs but do not want to throw good money after bad. Your help and/or experience- opinions are greatly appreciated.

RJ Allen
 
Imo you have tons of rocking and normally emeralds are nocturnal so seeing during the day should be rare... As for your fish I'd suspect the crabs are just in hiding because they are scared... My emerald is in a 26g full of rocking and is out all day long feeding of bryopsis and pellets I toss in for him :) however I don't have any fish which I fear he will hide more once I add them...
 
they come out at night...
unless they are in a totally relaxed and peaceful environment...

take a look in your tank after the lights have been off...pretty sure you will see them...
 
Guys
Thanks for responding and you may be right but I have spent a lot of time watching at night under my moon lights and in total darkness and have not seen them. I hope you are right. For the first 2 weeks the crabs were out a bunch but I did notice they were sensitive to me and would scuttle into the rocks if they saw me watching. Its been 4 weeks without a sighting. I also keep a visual inventory of the bubble algae and have not seen any reduction. I wonder how many e. crabs it takes to see some improvement.

I just wonder if anyone else has had a problem with my livestock and emeralds.

RJ Allen
 
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