Female cbs keep dying

[Bostave]

I had a healthy colony of 60 odd cbs but over the last few months my females kept dying. I have three males left now. The tank is part of shrimp rack with sump based filteration and uv, weekly water exchanges. My crs on the other had are doing extremely well. Any views regarding this would be highly appreciated. 

[neo-2FX]

@Bostave Are you still having issues?

[Bostave]

Hi, all that was left from the cbs were the males. So I sold them. Just have crs, Chocolates, blue velvets and carbons in the four compartments of the shrimp rack. 

[NoGi]

So no issues with the remaining breeds? Could it have been a moulting issue?

[Bostave]

Not sure. I saw moults in the cbs, crs and sw which I had then. Sw and crs did especially well as there were 6 or more females berried and I could see shrimplets from them. The cbs however did not. The females started to stay behind in the tank, stayed near the spring filter and dead in a week. All four compartments got the same water, foods and mineral powders. 

[NoGi]

Bummer, at least your current stock is doing ok now.

[zn30]

@Bostave how are the shrimp that have now occupied/moved into the CBS tank? Did you change anything in this tank that the CBS were in prior to moving in the new shrimp? 

This might sound silly, some may even wonder why I mention this, however I've read that if you have one type of shrimp breeding well in a shared tank that is for example CRS and Cherries, the dominant breeder slows down the breeding of the other species even causing death to berried females. Myself my CRS are really breeding well, ATM, and my cherries seem to have slowed down they share a Aqua mode 900 tank.

I understand your tanks share a sump setup so maybe this may have credence for your setup. I don't have real proof of this just my current observation. I am slowly placing the cherries into separate tanks for Rili, snowballs, tangerines, etc etc. 

Food for thought, I wonder if anyone else has experienced any thing that would strengthen or debunk the above.

[Bostave]

I have carbon rilis where I used to have cbs and the have flourished. I only keep one shrimp variety in each chamber. I cleaned the sump and have been using the compartments as isolated tanks with sponge filters and tetra whisper filters in each. This did not stop the cbs from dying.