Whodunit in the tank

fixedpoint · 08/20/2014, 10:18 AM

It has now been two months since I finished cycling my tank and I'm happy with how my tank is progressing. However, the one area where I've had a bit of trouble is keeping some varieties of mobile invertebrates, especially nassarius snails (3), fighting conch (1), and porcelain crabs (2). All of these have gone missing in my tank (30 gallon) with only scant evidence left behind -- missing claws for the 2 porcelain crabs and a possible shell for the conch (It's hard to remember if the white shell that I think may have been the conch was actually added to appease my one small blue-legged hermit crab).

I've scratched my head a bit to figure out what may have happened. Are the nassarius snails (and conch) just buried and will they come out later? Did they starve since the tank was new and I only had one fish so perhaps there wasn't enough to eat? Did something take them out (I've got one small blue-legged hermit crab, a cleaner shrimp, two pom-pom crabs, other snails, 3 sexy shrimp, and a smaller clownfish)? Ideas?

A few facts to help: the nassarius snails disappeared very soon after being added to the tank. The porcelain crabs didn't seem to like each other. The porcelain crabs and the conch disappeared after about one and a half months. I have never seen any aggression except for between the porcelain crabs. I don't think I overfeed so perhaps there just wasn't enough food in the tank. Water parameters are:

Ammonia 0, Nitrite 0, Nitrate 4 ppm, Salinity 1.025, Temp 78f, Ph 8.3, Alk 7.56 dKH, Calcium 375 ppm, Magnesium 960 ppm, Phosphate 0

I'm just wondering what may have happened so that I don't try to replace them to only have the same thing happen again.

hogfanreefer · 08/20/2014, 10:55 AM

Inverts are very sensitive to changes in water parameters. Sometimes in new tanks things aren't very settled until several months in. That could be it.

Your Magnesium is very low and your calcium a little low. Don't know if that could have anything to do with it.

Be on the look out for hitch hikers if you used live rock. I had two polyclad flatworms and a couple of whelks. These types of critters can be invert predators.

Dearth · 08/20/2014, 12:22 PM

Could be they didn't handle your tank parameters they tend be be fussy about changing conditions

You could also have a hitch hiker preying on them it could be anything from a crab to predatory shrimp to enucid worm

Or it could be simply hiding in the rock work/ sand

08/20/2014, 10:18 AM	#1
fixedpoint Registered Member Join Date: Apr 2014 Location: Bay Area, California Posts: 134	Whodunit in the tank It has now been two months since I finished cycling my tank and I'm happy with how my tank is progressing. However, the one area where I've had a bit of trouble is keeping some varieties of mobile invertebrates, especially nassarius snails (3), fighting conch (1), and porcelain crabs (2). All of these have gone missing in my tank (30 gallon) with only scant evidence left behind -- missing claws for the 2 porcelain crabs and a possible shell for the conch (It's hard to remember if the white shell that I think may have been the conch was actually added to appease my one small blue-legged hermit crab). I've scratched my head a bit to figure out what may have happened. Are the nassarius snails (and conch) just buried and will they come out later? Did they starve since the tank was new and I only had one fish so perhaps there wasn't enough to eat? Did something take them out (I've got one small blue-legged hermit crab, a cleaner shrimp, two pom-pom crabs, other snails, 3 sexy shrimp, and a smaller clownfish)? Ideas? A few facts to help: the nassarius snails disappeared very soon after being added to the tank. The porcelain crabs didn't seem to like each other. The porcelain crabs and the conch disappeared after about one and a half months. I have never seen any aggression except for between the porcelain crabs. I don't think I overfeed so perhaps there just wasn't enough food in the tank. Water parameters are: Ammonia 0, Nitrite 0, Nitrate 4 ppm, Salinity 1.025, Temp 78f, Ph 8.3, Alk 7.56 dKH, Calcium 375 ppm, Magnesium 960 ppm, Phosphate 0 I'm just wondering what may have happened so that I don't try to replace them to only have the same thing happen again.

08/20/2014, 10:55 AM	#2
hogfanreefer Registered Member Join Date: Mar 2012 Location: Conway, AR Posts: 2,117	Inverts are very sensitive to changes in water parameters. Sometimes in new tanks things aren't very settled until several months in. That could be it. Your Magnesium is very low and your calcium a little low. Don't know if that could have anything to do with it. Be on the look out for hitch hikers if you used live rock. I had two polyclad flatworms and a couple of whelks. These types of critters can be invert predators. __________________ DSA 155,Custom Trigger 42" sump/refugium, MP40 X2, MP 10 X 2, AI Hydra 52 X3, Apex controller, Tunze ATO Current Tank Info: DSA 155 gallon, mixed reef, SPS and wrasse dominant

08/20/2014, 12:22 PM	#3
Dearth Registered Member Join Date: Aug 2014 Posts: 14	Could be they didn't handle your tank parameters they tend be be fussy about changing conditions You could also have a hitch hiker preying on them it could be anything from a crab to predatory shrimp to enucid worm Or it could be simply hiding in the rock work/ sand __________________ My tank is nothing but a smorgasbord for my cats.......