Crustaceans dying

[MIkemare]

Hello All,

Newbie to this forum.

I have a small reef tank (30g) with a rather unique problem. Let me list the specs of the tank.

Lighting - Coralife HQI MH 150w 10k & Current USA 80w Orbit strip 40w 420/460, 40w 6700k/10k.
Filter - Eheim Pro Wet/dry 2224, Red Sea HOT P Skimmer
Conditions - 0 Trite, Trate, Ammonia, Phosphate, Copper. 350 Calcium, 8.15 PH, high alkalinity. Temp 79
Water Changes 10% bi-weekly using Kent Salt.

Now for the problem. All of the crustaceans and snails in the tank are dying. Also am losing select pieces of coral (namely a mushroom and zoo polyp).
The crabs do not outright die, but lay in weird positions (back, side, hanging upside down with legs fully extended, etc) and the snails seem to also hang out of their shells, or sit in once place for days before dying. Both the snails and the crabs move and twitch randomly, but then go back to a dormant state. This process takes 3-5 days and then the creature dies (probably from stavation as they do not seem to be eating during this).

I have four fish in the tank that seem unaffected (eating, bright colors, etc), a purple striped red sea goby, a pair of neon blue gobies, and a black capped baslet.

Thought it might be a copper or heavy metal problem, but we use chemicals specifically designed to not add heavy metals. We also use a boyd carbon bag periodically in the wet/dry.

Since the problem started, i have implemented 2 a week 10% water changes. After three weeks, the problem persists.

Any help at all would be appreciated!

Mikemare
Keeper

[Cosine]

Sorry to hear about the losses... always bad to lose anything?
A few questions for you
did you buy the tank new?
how long has it been setup?
why kind of water are you using? (tap? distilled? ro?)
what additives?
about how many snails/crabs have you lost?
hold off on adding anything until we figure this out. well get to the bottom of this

Also welcome to TRT!!

[DSB]

Your Ca. and ph are low.

[coralfreak]

The Ca is ok if he's only keeping softies and lps but low if he's keeping sps. Your pH is ok too. What's your salinity level? That could be the problem if it's too low.

[tabwyo]

check your temp as well. The snails hagin out sounds alot like heat stress as well.

[MIkemare]

Thank you for the help and the welcome, Cosnine, littlefishy, and coralfreak!

Littlefishy> I do not think the PH or the calcium are the problem, although the calcium is usually closer to 450 (was low the last test). The calcium and ph would not explain the deaths. nor should the salinty. This is a real stumper.

Coralfreak>Salinity is 1.0245. This is the usual salinity I keep in the tank.

cosnine> Yep, tank was bought new, been set up for going on 2 years now, last month I was breeding zoos and star polyps in the tank in the exact same conditions. Only recent additions where two zoo frags I bought about a month ago. Quite small (about 20 polyps total).

Have lost about 10 RL Hermits, 4-6 cucumbers, 6-10 atlantic turbos, 2 emerald crabs, 3 porcelain crabs, 1 CBS shrimp, and currently there is 1 emerald crab, 1 CBS shrimp, numerous snails and mini crabs that seem to be afflicted.

Using RO water with RO Additive.

We use a wide range of additives, mainly Kent and Coralife. Same exact mix of additives I have been using for over 2 years now.

[MIkemare]

Originally Posted by tabwyo

check your temp as well. The snails hagin out sounds alot like heat stress as well.

I keep a stable temp of 78-79 degrees. Never goes above 80 without an alarm waking me up and scaring the h*ll out of me.

[Loverotties]

Is your skimmer doing anything different? More foam or different color?Sounds like heat or is your tank grounded?(they mite be dieing of shock!)

[MIkemare]

oo

Originally Posted by tabwyo

check your temp as well. The snails hagin out sounds alot like heat stress as well.

[MIkemare]

Not sure why heat keeps coming up, the tank is stable at 79, and I have never been told in my 18 years of doing this that 79 degrees is too hot for crabs and snails, especially considering that they have been in that temp for almost 2 years.
The skimmer is doing the same as always, moderate thickness dark "glop". The tank does not have a probe for electric, but I have always noticed fish act different when an electrical current is in the water (not to mention the tingle i always get when I put my hand in the water), and I have not noticed any of these things.

[DSB]

Seem's to be, the only things that have changed are your ca & ph.

[tdwyatt]

Curious as to how your perform your top off for this system for your evaporative losses. How do you do this, nd how often? Have you tested your RO water?

Where did you get your snails and crabs, how were they transported to their home, and how long have you had them?

You may have already listed this, but what are the fishes in your system? How old is this actual system (since its current set up?)


and Welcome to TRT

[MIkemare]

Originally Posted by tdwyatt

Curious as to how your perform your top off for this system for your evaporative losses. How do you do this, nd how often? Have you tested your RO water?

Where did you get your snails and crabs, how were they transported to their home, and how long have you had them?

You may have already listed this, but what are the fishes in your system? How old is this actual system (since its current set up?)


and Welcome to TRT

We have pre-mixed RO water that we use for water top off. We never keep the water for more than a week before replacing it. We top off once every other day or so, perhaps a quarter gallon.

The RO water straight out has a PH of 7.1 & low alkalinity, we of course buffer it up, 0 on all major toxins (ammonia, trate, etc) and 0 on the copper readings.

BTW thanks for the help and welcome!

System is coming up on 2 years old, we have a blackcap baslet, a pair of neon gobies, and a purple striped goby in the tank.

The crabs and shrimp range from 1-2 years old, none are new really, bought most of them from a LFS, but a few came from assorted places from the internet.

[MIkemare]

Originally Posted by DSB

Seem's to be, the only things that have changed are your ca & ph.

Thank you for the help, but I do not feel that a CA of 350 and a PH of 8.15 would cause this kind of issue.

In fact, when I used to work at a LFS, most customers reef tanks where lucky if they had a calcium reading at all, and the crabs did not act this way in those tanks. (the coral sure hated it though).

I have also seen most saltwater creatures handle a PH in the 7.5 - 7.8 range without any lasting problems.

Forgot to mention, the reason the CA is low is because I have a star polyp rock that is (was) growing at an very rapid pace, even adding full doses of calcium powder was not getting it above that due to the growth.

[tdwyatt]

Originally Posted by MIkemare

We have pre-mixed RO water that we use for water top off. We never keep the water for more than a week before replacing it. We top off once every other day or so, perhaps a quarter gallon...

Evaporative top off every other day is actually a pretty big swing in salinity at one time on a regular basis: it represent an issue for crustaceans in particular, especially with such a small volume to start with. If your beginning salinity is at 1.025, and your system evaporates one-half gallon (US) in 2 days, this represents approximately a 3.5% increase in dilution effect when adding the water back to top off the system. At 35 PPT salinity, 30 gallons is approximately 120 liters with 4200 gms of mixed salts. Concentrating this down to 29 gallons would represent a salinity of 36.3 PPT, and although this may seem a small variation, if part of a bi-daily swing would represent a huge metabolic cost to the crustaceans and molluscs alike over time. As most of these types of creatures are quite sensitive to salinity swings, you will see a gradual die-off of these organisms, and any larger swings either way may cause group losses. These types of swings are even worse for creatues like the Asteroides seastars, where regular swings in salinity lead to rupture of semipermeable membranes in the ambulacral locomotion system these seastars use to drive their tube feet motion. Such swings in the environment of these creatures often leads to delayed tissue ulceration, occurring at times up to 4 to 6 weeks after the initial insult to the ambulacral tissues.

This may not be the only issue with the gradual losses, often it may be just enough to slow the specimens in question down enough so that other organisms more capable of dealing with the salinity swings (like fishes) may have an advantage, making these crustaceans and molluscs easy prey for hungry fish. It may be that there isn't really an issue with the tank or water column, rather the daily or bi-daily swings in salinity raising the stakes for these organisms.

Most of these creatures have evolved in rock steady salinity, and have slow or poor adaptive mechanisms for salinity swings, so even small 3% swings in salinity will hve large effects of the specimens in question. It really is a sin to take 3 to 4 hours to acclimitize these more difficult animals, then take 10 seconds to make a 3-4% salinity change with top-off additions.

As I said before, this may not be the issue, but it certainly is not helping.


HTH