Explain these shrimp deaths?

[fatboy]

I'm so upset. About 4 days ago both of my large macrobrachium shrimp died within a few hours. I've just noticed that my m. pilimanus (chamelon shrimp) has died too. :(

I'm trying to figure out why they died so close together. The water conditions are good, no ammonia/nitrite/nitrate being picked up on my testra test kits. My water change routine hasn't varied from 25% twice a week. none of the cherry red or amano shrimp have died and they appear to be thriving. The fish, dwarf puffers and otos, are also doing well.

The only changes have been adding some rock, bogwood and using a different water conditioner (seachem prime). The first 2 shrimp died a few days after it was put in the tank. However, the PH is the same, as is the general and carbonate hardness. It hasn't changed in months, and even though I think they wereto blame I have no good explanation.

None of these 3 dead shrimp have molted in at least 6 weeks. Prior to that it was every 3-4 weeks, and they were all small when I bought them less than 4 months ago. The other shrimp are molting and thriving.

Any thoughts on why they died? Could the rocks or would have introduced something I've not discovered yet? I can't figure out what water conditions would mean that only the macrobrachium shrimp die and the others are unaffected.

[Walter]

Hmmm, I'm sorry I don't really know why.. You'll have to wait for the experts to help you.. Shrimps usually die of bad water parameters.. Since in your case it was good.. I have no good reason as well..

[Robert]

Hi,
it is summer and the tap water is relatively warm. These means there are better conditions for bacteria etc. . To prevent this they often add more chlorine or chloramine to the water. At least here in Germany they do this and they don't say a word about it. This caused many problems in the last years and I prefer to do only small water changes in summer. If they don't do it, you get sometimes mysterious bacteria infections of your fishes. This cost me last year most of my guppy strains. I also lost my green shrimps because of this.

Normally you see the effects of added chemicals about 2 till 3 days after a larger water change. I had to make this experience several times in the past. There is not much you can do. Maybe you use a bit more of a water conditioner as a prevention.

That only your Macrobrachium shrimps died is strange but maybe they react faster or they are more sensitive to fast changes of their environment. My Macrobrachium are much more sensitive and so I lost most of them again :undecided . I don't know why exactly and so I can't stop it.

Regards and good luck with the remaining shrimps!

Robert

[fatboy]

Thanks for the comments, Robert. I spoke to the local water company who will check and get in touch. They also suggested more water conditioner so I think you are right. They also mentioned to be very careful after sudden warm spells like we had recently. They add a lot more 'conditioners' to prevent algae and bacterial blooms.

The water actually SMELLS worse, like a swimming pool, and I'm going to treat it and let it sit with an airpump running.