Mysterious RCS die-off in the midst of Sri Lanka Dwarf Shrim

Terran · Post by **Terran** » Sun Oct 14, 2007 3:35 pm

I got 5 Sri Lanka Dwarf Shrimp and 5 Malaya Shrimp on Sep 20. I put them in an aged ten gallon tank with several juvenile/baby RCS…. This was one of my more successful tanks that my RCS breed in regularly so in preparation for my new arrivals I had removed all the older RCS…

so there was still about 8-10 RCS babies in the tank when the new guests arrived....

Everything was fine at first…all the shrimp were growing steadily and acting healthy.

Now the majority of all the shrimp in this tank are about 3/4cm-1cm. Four days ago I woke up to find three red shrimp dead (they were not the Sri Lanka….2 were definitely cherries…one I wasn’t sure because it had fallen apart quite a bit)….
I was concerned but I did not want to do a water change yet because the tank conditions were fine….
Day 2 of the trouble a cherry looked sick…and I could only find two Malaya who both looked healthy and all five Sri Lanka looked perfectly happy….
Day 3 of the trouble another cherry was dead and I could only find two Malaya who both looked healthy and all five Sri Lanka looked perfectly happy…
Day 4 of the trouble, another cherry was dead and two looked sick All five of the Sri Lanka looked perfectly happy and I found four of the Malaya Shrimp(finally!.. I suspect the other one is hidden in there somewhere) and they appeared happy and healthy….On day four I decided to do a water change….

Now I don’t particularly care about losing these cherries as unfortunate as it is because I have several other tanks with thriving communities….I am just concerned with my new arrivals and establishing their population…

Anyone have any ideas or advice?

Water parameters have been fine (or at least appear to be so within the range of testing strips)
Temperature has not fluctuated
Nothing appears to have changed in the tank with exception of the new tank mates (the new shrimp)

I have one idea….

The cherry shrimp in this tank I have been heavily inbreeding so that I could get a very general idea to what extent these shrimp could be affected by inbreeding…..
I had one female have babies…then I had her be fertilized by one of her offspring (then removed this offspring)…when her new offspring grew old enough I had her fertilized by this new offspring(then removed this offspring)….
This was repeated five times so that the cherries in this tank had a mother that was also their grandmother and also their greatgrandmother and also their greatgreatgrandmother and also their greatgreatgreatgrandmother….. So my idea is perhaps this level of inbreeding has made them susceptible to disease or just suffer from suchl poor health that early deaths occured…..

It’s the only thing I can think of so far since the other shrimp appear to be unaffected….(so far ....*crosses fingers*)

Neonshrimp · Post by **Neonshrimp** » Sun Oct 14, 2007 6:51 pm

It is good that you have bred your shrimp with such controlled lineage and record. Did you do this to get better color or another reason? I have always kept my RCS all in a breeding tank and moved individuals/groups out when I wanted. I justs haven't had the time to selectively breed them yet.

How are the RCS doing in your other tanks/colonies, have you had this problem with the others?

Terran · Post by **Terran** » Sun Oct 14, 2007 9:34 pm

It really wasnt that much control involved....

Thats how the idea started out I had a really dark red female that was fertilized....I isolated her in a ten gallon tank all alone....once she had her babies I started removing her female offspring untill there was only males left and their mother....then once she was fertilized again I removed all the males....I just did this over and over again....so there wasnt really any need to keep a record...its just keeping one female in a tank and removing everything else once she gets fertilized....

My RCS in the other tanks are all doing fine

Neonshrimp · Post by **Neonshrimp** » Sun Oct 14, 2007 10:20 pm

Have you found the offspring of the dark red female to be improved from your original shrimp.

Have you seen any of your new arrivals attack the RCS? If you see injuries then this can be suspected. RCS are usually harty shrimp and can take more extreme conditions, like temperature.

Terran · Post by **Terran** » Mon Oct 15, 2007 9:15 am

Well the first and maybe the second inbreeding seemed to improve the color slightly...but I may just be imagining the improvement or just a product of them being in different tanks....After that though there was no noticible change...and perhaps even a lessening of color intensity(hard to say now though because the current offspring are still young)...

I have not seen any acts of aggression from the new arrivals (I didnt think Malaya and Sri Lanka could even be aggressive).....And I havent seen any injuries....

Post by **Mustafa** » Tue Oct 16, 2007 11:53 pm

Neonshrimp wrote: Have you seen any of your new arrivals attack the RCS?

When was the last time you saw any dwarf shrimp attack anything?

Dwarf shrimp do not have the means to attack and hurt other shrimp or fish.

As for the problems with the RCS...it's hard to say what happened. As many water quality problems have a delayed effect, i.e. the problem occurs but the shrimp don't die off right away but start dying even *after* the problem has disappeared, it's hard to say what exactly happened to your shrimp. Fact is that almost *any* sudden, large change to a shrimp tank can affect your shrimp. If you have done any sudden changes that went along with taking out your old RCS out of the tank, that could be the culprit. Either way, the best thing to do is just sit tight and wait until the tank fixes itself. When the tank has fixed itself the shrimp will be out in the open and grazing.

Neonshrimp · Post by **Neonshrimp** » Wed Oct 17, 2007 12:11 am

When was the last time you saw any dwarf shrimp attack anything?

I have actually witnessed CRS attack female RCS on three seperate occations. It looked as though the CRS were attaching themselves to the RCS, almost as if they were trying to mate with the females. The RCS would try to shake the CRS off. If they were able to, another CRS would attach onto the RCS. The first two RCS that were attacked died. On the third occation I seperated the RCS and she lived for a few more hours before dying of shock/injuries.

This is the first time I had seen any of my shrimp attack anything and that is why it came to mind in this case. I was just wondering if this happens when different types of shrimp are keep together.

Post by **Mustafa** » Wed Oct 17, 2007 1:01 am

I can guarantee you that the death of your RCS had nothing to do with the CRS clinging on to the RCS. If you ever get the chance to look at the "picking legs" of dwarf shrimp under the microscope, you will see that they are basically small versions of what filter shrimp have. They can't damage much more than algae and biofilm with that. Imagine you have something similar to featherdusters for hands and try to damage things with them by grabbing...it just won't work. Plus, in all these years with dozens of species of dwarf shrimp I have not seen a single "attack" initiated by dwarf shrimp against other shrimp (and there is probably not another person in the world at this point that spends more time observing shrimp than I do).

Yes, they will grab at each other, call it "fighting" if you will, if they ty to grab food from each other, but that's not an attack. Yet, the internet is full of people who report that their "amano shrimp" or "cherry shrimp" grabbed fish or other shrimp and ate them. In all cases it's dying fish/shrimp (i.e. shrimp/fish that can barely move) that are being picked at by other shrimp. *That* happens all the time.

Bottom line is that you may just not have realized that your RCS was already on the way out.

Neonshrimp · Post by **Neonshrimp** » Wed Oct 17, 2007 8:20 am

Bottom line is that you may just not have realized that your RCS was already on the way out.

This is the most likely explaination of why the RCS died. It's just that I had also never seen anything like this happen before and it has not happened since.

Terran · Post by **Terran** » Wed Oct 17, 2007 2:12 pm

Mustafa wrote:
As for the problems with the RCS...it's hard to say what happened. As many water quality problems have a delayed effect, i.e. the problem occurs but the shrimp don't die off right away but start dying even *after* the problem has disappeared, it's hard to say what exactly happened to your shrimp. Fact is that almost *any* sudden, large change to a shrimp tank can affect your shrimp. If you have done any sudden changes that went along with taking out your old RCS out of the tank, that could be the culprit. Either way, the best thing to do is just sit tight and wait until the tank fixes itself. When the tank has fixed itself the shrimp will be out in the open and grazing.

Hmm I had not really thought that something could have happened to cause a probelm with those shrimp long before I introduced the new shrimp....The only thing I can think that I did anytime recently was when I removed the adult cherries from the tank....

But that was like about 4 weeks ago....So that would mean it took about 3 weeks to even have a visible effect on the native shrimp(the deaths)....but seemingly not have any effect on the new tank mates who only missed that event by 3 days...(Unless it was just that one day when the moving happened that did it)

Oh well all seems well now....The new tank mates are almost egg carrying size....

Terran · Post by **Terran** » Fri Nov 02, 2007 6:37 pm

Well now some more time has passed. I have one berried Sri Lanka and all five of these shrimp seem healthy...so hopefully Ill have some babies soon and will be able to relax a bit when it comes to their population size....

However I thoroughly checked the tank and it appears that I only have 3 Malayas left....I think the chances that one is hiding somewhere is slim since there really isnt much to hide behind in this tank...only grass and two rocks....
So somewhere in that string of deaths I had two Malayas likely die....

I am a little afraid that I have only females left in my Malaya population....I think one might be a male though, but since I consider myself very inexperianced in sexing various shrimp species I would appreciate some help in verifying my situation....

I think this is a female....(pretty sure)

I think this is a female.....(pretty sure)

But,
Is this a male? (somewhat sure maybe wishful thinking or maybe just in panic)

Neonshrimp · Post by **Neonshrimp** » Fri Nov 02, 2007 6:48 pm

Thanks for the picture, best wises on improving your populations

.

Terran · Post by **Terran** » Fri Nov 02, 2007 6:49 pm

Did you read my question?
I wasnt sharing pictures I wanted to know if I was correct or if I am going to need to purchase more Malaya

badflash · Post by **badflash** » Fri Nov 02, 2007 6:53 pm

The 1st 2 are females (IMHO), and the last may be a male, but a closer pic would help. Mustafa can likely tell at a glance.

Terran · Post by **Terran** » Fri Nov 02, 2007 6:56 pm

Ill work on coaxing them all back to the front of the glass....

Mustafa probally could tell at a glance....

my gut feeling is that they are all females...and that the third one is just a less developed female....