Mysterious shrimp deaths

[TWallace]

Last night, one of my two cleaner shrimp was acting strange. He was not near his buddy (mated pair) and was out in the open along the glass, not moving much. I also noticed his color had changed from pale yellowish to amber. My flame hawk seemingly knew the shrimp was dying and was staking it out, waiting for a meal. The shrimp died a couple hours later and the flame hawk got his meal, but it was obvious that the shrimp died on his own, not with the help of the flame hawk.

Later that night after the lights were out, I looked at the tank with the flash light and found the other cleaner shrimp was now dead and being eaten by nassarius snails.

A couple weeks ago, I also noticed that my large fire shrimp was dead and couldn't find his smaller fire shrimp buddy. I had the two cleaner shrimp for around a year, and the large fire shrimp for about 8 months, smaller fire shrimp for maybe 3 months.

I first suspected a contaminant in the water that's harmful to inverts, or possibly I had let the salinity drop too low. I don't know what contaminants could be in the water, but I tested the salinity with a refractometer and it's actually slightly high, 1.027. Also, the urchins, snails, starfish, hermit crabs, corals and clams all look fine. You'd think any contaminant or water quality issue that could kill shrimp would also kill hermit crabs, and possibly other inverts.

I love shrimp and would like to get more, but I'm afraid that something in the tank is causing them to die. I measured nitrates last night as well, and they're only at 2.5 according to Salifert test kit. Temperature is normal too, 79.5.

The only recent changes to the tank is that I removed my large GBTA in preparation for selling (it's too dangerous to my SPS). My cleaner shrimp typically hung out underneath the anemone, maybe for protection. The flame hawk never bothered them (he's small, and the shrimp were pretty big), until the one started to die. The second one died after lights out, when the flame hawk was asleep, so I don't suspect the fish has been killing them. The cleaner shrimp and flame hawk coexisted for at least a year peacefully.

 

[Reeferdude]

Maybe the Hawkfish grew to a size large enough to eat the shrimp??? I've never had good luck with Shrimp...Seems like they always end up as food...

 

[Jan]

What a bummer, Tom, and very mysterious too. I'd be inclined to think about contaminants also. But I also don't understand the effect of the higher salinity on shrimps compared to how other animals react to it.

Did you look in your sump to see if anything is in there that shouldn't be? Did you change salts or any other kind of additive? What about the expiration dates on your current additives and test kits? Anything expired?

How soon after removing the anemone did this start happening?

 

[TWallace]

I haven't changed salts or additives in a long time. The fire shrimp actually both died before I removed the anemone. The two cleaner shrimp died about 4 days after removing it.

The only additive I use is Mrs. Wages for calcium/pH boost. I don't think there is an expiration date on that. I've checked the sump and I don't see any foreign objects in there. Just some sponges living underneath the overflow hose.

I don't suspect the flame hawk has been killing them. He's less than 2 inches long, which is shorter than any of the shrimp that have died. Plus, I never saw him bother them until the cleaner shrimp last night was clearly on the way out and the flame hawk setup camp near it waiting for it to die.

 

[Jan]

OK so to summarize your water parameters,

sg is 1.027 (still or has it come down?)
nitrates are 2.5 (Salifert)
temp is 79.5


Can you post your levels of alkalinity, ammonia, nitrites, calcium and magnesium? Maybe something will suggest itself. How old is the Salifert nitrate test?

 

[Herefishyfishy]

What do the shrimp eat?

 

[TWallace]

Well nothing now, they're dead . But they ate whatever stuff I fed my fish. The cleaners were quite aggressive eaters and would hoard large chunks and snack on them for a long time. I fed the fish mysis, brine, several kinds of frozen formula (I have a variety bag of it), occasionally prime reef flake food and formula 2 pellets.

Jan, here are some more test results:
pH: 8.4
Alk: 5.5 dKH (Salifert), 5.0 (Elos)
Ammonia: 0
Nitrite: 0
Calcium: 340ppm
Magnesium: 1680ppm
I did not lower the salinity, as I don't believe 1.027 is high enough to bother anything. The ocean is typically 1.026, right?

The Salifert nitrate test kit is about 6-8 months old. I have a backup kit from Aquarium Pharmaceuticals that says nitrate is 10, but I trust Salifert more. The AP test has been out in my storage closet exposed to the heat and cold for months.

The calcium is a bit low, usually it's 420. Maybe I need to add more kalk powder to my top off bucket. The mag is high on purpose, in order to kill off bryopsis and keep it gone. If it dips below about 1500, bryopsis starts to grow again.

I've been keeping a close eye on hermit crabs today, figuring that whatever water condition killed the shrimp would also harm the hermits. So far the blue legs seem to be cruising around fine. The only scarlet leg one that I can find has been sitting still all day. He was upside down on the sand. I moved him to the top of a rock and put him right side up. Since then he's been gripping the rock under him, but not moving. I'm not sure what conclusion to draw from this.

All of my fish, corals, clams and other inverts still look great through this, it's only the shrimp that have died. When the first cleaner died last night, I thought no big deal, they don't have long lifespans and I had him for about a year. The second one dying the same night is too much of a coincidence for me to believe they were just old. My girlfriend suggested the second died of a broken heart, since they were a mated pair .

 

[Jan]

Tom, you need to get your alkalinity up ASAP. 5.5 or 5.0 is too low. NSW levels are ~7.0, ranging from 6.5-8.0 mostly. Problems/deaths start to happen when it dips below 6.0. I've read quite a few accounts of this (especially when I had my own alk problems a while back, only on the opposite end of the scale).

I also think that the salinity is too high but I don't know enough about that to speculate about the repurcusions.

And your calcium is too low. If it's been low for quite a while then possibly the shrimps may have been effected by this as well.

Possibly the combination of all of these things, the high sg, low alk and low ca....maybe all together it was bad for your shrimp.

I think you should definitely get that alk up though....IMO it is the most important parameter to keep an eye on. Yes, I speak from recent (bad) experience and I lost a couple of corals because of it.

 

[Damsel13]

ok this is a weird way out theory but I think the shrimps got "too friendly" with the softies or anemonie in the tank. Or else there is just too much softie warfare going on and the shrimp can't doesn't know how to stay out of the way. Then again, maybe they were just old ://.

 

[TWallace]

I just did a 35% water change. I was going to do one today anyway. I also added some Kent Superbuffer dKH after the change. Salifert and Elos both say 9.0 dKH now. I added a lot more pickling lime to my top off bucket and am about to dose some Kent Turbo Calcium and see if I can get the calcium back up over 400. I'm not sure if either alk or calcium led to my shrimp's deaths, but I have no other explanation at this point.

 

[Jan]

OK, that's a really big jump from 5.0 to 9.0...

keeping my fingers crossed that you have no more problems but you might, from the sudden swing in alk.

plus, don't the buffer and the pickling lime do the same thing--raise alk? I would not add anything else that raises alk until you can get it stabilized btwn 8-9 dhk...

 

[TWallace]

I added more pickling lime to the top off container, but it has not yet pumped water from that into the sump. I don't know if kalk raises alk. I just know it raises calcium and pH. So far nothing in the tank is acting abnormally due to the alk boost. All clams are still open wide, as well as corals. Fish all looking normal, too.

I think it's possible that the scarlet leg hermits are just more nocturnal than the blue legs, which would explain their inactivity.

 

[Damsel13]

my scarlets are almost exclusively nocturnal.

 

[tamarindthai]

you were off balanced ,don't trying to get back to too fast ,,becareful about your sps might stress out,should take 3-4 day to do it.slow drip is the best.

 

[thekingfish]

I added more pickling lime to the top off container, but it has not yet pumped water from that into the sump. I don't know if kalk raises alk. I just know it raises calcium and pH. So far nothing in the tank is acting abnormally due to the alk boost. All clams are still open wide, as well as corals. Fish all looking normal, too.

I think it's possible that the scarlet leg hermits are just more nocturnal than the blue legs, which would explain their inactivity.

Kalk raises both alk and cal equally.

 

[TWallace]

Still no adverse affects on anything in the tank today. All corals/clams are opened up normally. Maybe I'll buy another cleaner shrimp soon and see how it does.

My clownfish have decided on a new host since I removed their anemone:

Strange that they chose zoanthids as their new home. There are a few toadstool leathers, a goniopora (glad they didn't pick that) and xenia in the tank. I figured they'd pick a toadstool.