My name is Alan. I've been reading bits and pieces about shrimp on PlantedTank for some time now and you have helped me a lot in maintaining healthy shrimp tanks. So I'd like to start off by saying thanks!!
I've been keeping red cherry shrimp (Neocaridina) for about three years. Currently I have a problem with a 4ft, 100L tank that houses roughly 600 cherry shrimp. I set this particular tank up about 8 months ago. It was fully cycled before adding any livestock and I started with 50 shrimp.
The params are:
Temp - 24°C
PH - 7.5
GH - 7
KH - 3
Ammonia - 0
Nitrite - 0
Nitrate - 2.5
TDS - 190
I use the liquid API Test Kit for testing.
I have no plants.
1cm depth of gravel (bought from a shrimp-specific shop).
2 large pieces of bog wood.
3 of the double foam filters.
2 Air stones.
An 8 litre canister filter (was new when added to the tank and sponge filters are on the intake pipe).
Lights on for 10 hours per day on a timer.
100% RO/DI water re-mineralised with Salawesi Mineral 7.5.
Tantora Mont Powder.
2 Dried Catappa leaves.
1 Dried Guava Leaf.
I added 3 alder cones about the time the problem started, but have since taken them out.
Shrimp King Complete.
GlasGarten Shrimp Dinner Gran.
Tantora Amaranth Leaves.
I feed just one of these per day, on rotation, and they have 1 - 2 days per week with no feeding.
Everything had been going well up until about 3 weeks ago. All shrimp were molting, eating and breeding very well and then suddenly I began to loose a few shrimp every day. All of the dead one's had the famous white crack on their back. Obviously, the first things that came to mind were bacterial infection or GH issue.
The shrimp had no signs of bacterial infection. No cloudy body etc.. I ruled out poisoning also as I didn't have a mass die-off and nothing new was added to the tank. I also never use any sprays in the same room as the tank. I have not seen any sign of parasites either.
I did notice that the GH had risen from 6 to 10. Probably from evaporation due to the summer heat. I have spent the last 3 weeks slowly bringing it down to 7. However, the deaths are still continuing at a rate of about 10 per day. All sizes of shrimp are being affected, including the babies.
They freeze while swimming and gently float to the tank floor on their back or side. Their legs still move while they are on the floor, but they can't swim and the other shrimp swarm and devour.
Sounds like a failed molt right? However, I don't think this is the case.
I have had this before a couple of years ago with a different tank when I used to use tap water that had a GH of 16. I lowered it to 6 and the issue stopped, but it doesn't seem to be the same problem this time as the GH is well within the acceptable range.
Now, here's the strange thing. When I take out the affected shrimp, before the other eat them, I keep them in a separate container to observe. They will live for about 24 hours (sometimes longer), but their actual exoskeleton is peeling off. It's not a molt. I have seen 100's of shrimp molt in the past and I can guarantee that this is not what is happening.
Another thing worth mentioning is one day only shrimp measuring 1cm die. The next day they will be 5mm and the next would be 1.5cm. I don't get a mix of sizes die on any one day.
The red exoskeleton is literally coming away from the body leaving the "meat" exposed. By this time they are dead.
I was just wondering (if anyone is still reading after this long and boring post
) whether anyone has had the same issue or any idea what's causing it?
I'm well and truly stumped and would love to get to the bottom of the issue, so any educated suggestions are welcome.
Thanks for taking the time to read this and I look forward to hearing your ideas.