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Crs dying after moults

windyboona

Member
Joined
30 Oct 2012
Messages
53
Location
Wootton
Hi there , I seem to be losing a lot of crs the last few months usually a few hours after they have moulted , does anyone know what causes this ?
I have stripped down the tank they were in and cleaned it cause I thought it might be bacterial , but now the same is happening in there new tank .
My water paras are:
TDS-144
PH-6.8
GH-5.6
KH- 1.12
Any theories guys !!
 
You maybe need to raise your tds a bit. What do you use to re mineralise your water?
 
Was there ever multiple deaths at one time or is it one every now and again. If it were multiple I would say there's a water quality issue.

Singular deaths for me are baffling post moult especially when it appears the water quality is fine, I lost three CRS in a couple of weeks after introducing them to the tank all the others survived, but in all that time (5 months) they have never produced offspring whereas the cherries are not having that problem. In the past week I have lost a single cherry post moult and at that time I didn't attribute any reason for this, however I made a curious observation a day or so later when a friend was round and he was looking in the tank and announced that one of the cherries was on its back being eaten, sure enough one mature female was on its back and had a shrimp on top of its swimmerets but it did not appear to be eating and the shrimp laying on its back was still alive, there were other shrimp swarming over trying to gain access. I got the tweezers out and carefully move toward the conglomeration which separated and the shrimp that had been on its back righted itself, with difficulty it tried to swim away but was immediately set upon, but crucially I noticed the shrimp on top thrusting vigorously, ahaaaa that's what's happening, it was a female and she had moulted so was ripe for mating. She was being swarmed upon by other shrimp and the currently mating shrimp was not letting go to let the others have their turn, she's still on her back and appears too exhausted to escape so I break things up again and she manages to swim to hide in the frogbit at the surface. For about five minutes she was hunted for forcing her to swim away to a new hiding place. She survived, I'm assuming she needed to be free to harden her shell.

So my take on this is that these mysterious post moult deaths are females that have been either exhausted by mating and die before they are able to harden their shell or the mating shrimp does not decouple due to competition and somehow this weakens the female and prevents her from hardening her shell to prevent further encounters.

It's a wild stab in the dark, but it's all I've got!

:)
 
Hi, no they are single deaths,every time I see a moult I know within 4 hrs I'm going to have a death.
I have also witnessed the mass brawl on females after moulting and have thought the same as you,that the females are so exhausted after the badgering they receive they just can't get the time to harden there shells and recover.
I have plenty of berried females and lots of shrimplets in the tank though ,some even appear to be green hulks and snow whites :wideyed:
 
In my marine tanks I find the few shrimp I have seem to react positively to iodine dosing. Not knowing if this applies to freshwater also, I did a quick search... it seems the jury is still out on that one. Might be one to consider if nothing else works.
 
I can't get mine berried its so annoying, I think my CRS are majority male and when a female moults she will not let them mate. I posted a vid in my Journal of pheromone chasing behaviour and you can see when mating appears to look like it's going to happen it's quickly rejected and the presumed female darts off to hide. I introduced a couple of carefully selected (in the fish shop pointing, 'that one') blacks hoping one is at least a female.
 
If the female is not 100% happy in her environment she may not be saddled so has no eggs to fertilise despite the efforts of the males. I have seen my shrimp mate and it takes less than a second with mine. You could try removing males if you have so many that they are hounding the females to death, you only need a few to do the job ;) I've never had females die after moulting/mating so I would be inclined to think the problem was something else.
 
Previously I kept them at gh5 tds 160. Currently they are gh 5/6 tds145. You just have to slowly play around with the parameters to find the sweet spot.
 
You could try feeding genchems white pellet and I recently added a bit of cuttlefish bone.
 
Sorry to hear of your losses.
Some interesting suggestions made, I think the occasional deaths of shrimps is not easy to pin point.
My water parameters have been stable for many years for my CRS. Using RO and Bee shrimp mineral.

Temp; 22c/71f max.
TDS; 130
GH; 5
Nitrate; 0

I have over 500 crs, and 50 Blue bolts/ Kingkong spread over 5 tanks.

Incidentally i only introduce the shrimps to tanks that have been running for several months, and avoid disturbing things, apart from stiring the ADA substrate weekly.
Which the shrimps love, it brings them all out, to graze on the rotated substrate.
 
We'll I've slowly raised the tds over the last 3 days from 144 to 165 ,there have been 2 molts since then and no deaths so fingers crossed .
Thanks for all the advice pips !!
 
What a lot of shrimp keepers dont realise is tds is a measurement of everythin in the water of which not a lot is usefull to shrimps.
What is the tds of your ro water?
 
What a lot of shrimp keepers dont realise is tds is a measurement of everythin in the water of which not a lot is usefull to shrimps.
You'd be surprised how many of us do realise that and that is why you have to play around with tds to find what suits your shrimp/water. Since I started using rainwater with a tds of 2 I now keep the shrimp happy at a lower tds than when I used tapwater of a tds 45.
 
Sorry it wasnt a personal stab at you :)

OP
What is your tds before you remineralise?
I ask because I got aome from an lfs with a tds of 95 a while back.
 
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