Missing shrimp

[tripper]

I don't know if anyone will really be able to help me with this one, I am definitely stumped though. My tank has been in great shape for a few months now, except for some hair algae I've been fighting. I had about 5 peppermint shrimp and one cleaner shrimp in my tank for over 2 months. As we all know, peppermint shrimp hide all the time and you really will only see them at feeding time. Unfortunately, that's how my cleaner shrimp was too.

Anyway, in the last 2 weeks or so I haven't seen ANY of my shrimp. I think they may have all died or been killed, although I can't think of how that would happen. The only thing that has changed is I have been doing water changes to change from Oceanic to Instant Ocean salt.

The inhabitants of the tank are:
H. Irridis wrasse
Six line wrasse
Yellow watchman goby
Spotted Mandarin

It is a 72G bowfront. Water params as of last night:

pH - 8.2
Amm - 0ppm
Nitrite - 0ppm
Nitrate - 5ppm
Phos - 0ppm
Temp 80F
Salinity - 1.024

Any ideas?????

tripper

 

[schoeplein]

Inverts are the most succeptable to changes in salinity....

 

[tripper]

It wasn't a change in salinity. The salt mixture changed, which does have some affect on the chemical makeup of the tank, but I always match the salinity and temp of the new water to the main tank before doing a water change.

Any other ideas?

 

[Phyl]

This happened in my tank overnight. I never ever saw hide nor hair nor antenae of these critters ever again. You see remnants of molts when they happen... I have no idea how my entire shrimp disappeared overnight with no sign of them to be found anywhere.

In my case I think it was when my nitrates spiked (or the resulting water changes that I did back to back) that overcame mine.

Sorry to hear of your missing inverts.

 

[tripper]

I guess my question at this point is . . . is it safe to add a couple cleaner shrimp again? As I said before, all my water paramaters are great and the fish are all looking good. I would hate to add more shrimp though just to have them disappear again.

tripper

 

[Phyl]

I had 2, lost them. Added 2 more (2 days later: My husband did it, lol). Lost one. Added 2 more 2 weeks later and now I have 3. LOL. I think as long as everything is stable you could add more. I would be wondering what would happen to decimate your entire population all at once. That's a lot of shrimp to go missing. I would be starting to wonder if there could be an iodine issue in the tank. (do you do frequent/large water changes that would keep up the iodine? Do you dose anything?) I wonder if they weren't all competing for the iodine so were unable to molt? Did they molt frequently? Just a theory, mind you. I have 4 shrimp (1 peppermint and 3 skunk) in my 120; is 6 shrimp in a 72 crowded looking?

 

[MT79]

I think it would be a good idea to hold off on getting any new additions until your done w/ the salt mix change over. It may save you some $$ and headaches.

 

[kwan]

Do you have any predators in your tank? I caught my arrow crab a couple nights ago eating a cleaner shrimp leg like if it was a chicken drum stick. Thats the second cleaner he ate in the last 3 months. Pretty expensive meals I must say.

 

[tripper]

Phyl,

6 shrimps in a 72 was not crowded becasue the peppermints hid all the time. The reason I had so many was because I had an apstasia problem and the LFS was doing a 5 for $20 sale on pepps. I do bi-weekly 20% water changes and do not dose anything for this reason. However, I should probably by an iodine test kit and check it to make sure. I hadn't thought about the shrimp competing for the iodine in the water. Now that you mention it, I did not see many molts from them. That may have been the issue!!

Kwan,

I do not have any predators in the tank unless there is a hitchiker that I am unaware of. I try and keep a close eye on the tank too, so I don't think that is the issue, but who knows.

Either way, when I do decide to add more shrimp I will not have 6 like I did previously. I have no need for any peppermints at this point so I will probably stick to 2 cleaners or 1 cleaner and 1 fire shrimp.

Thank you all.

tripper