RCS deaths, any insight?

beeZer350

beeZer350

Likes Expensive Hobbies :(
Jan 19, 2008
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Over the past week or so I've discovered a dead RCS in my shrimp tank just about every day. All of them appeared to be juvies except the one yesterday. She was most definitely a full grown female. The tank has been running for 2+ months with no issues and the shrimp were in a different tank before this with no issues. Filtration is a sponge filter and the tank mates are a school of corydoras pygmaeus.

Water params last night before a 30% wc: 0 ammonia, 10ppm nitrate.

Any ideas?

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Any large temperature or PH swings? Any change in feeding lately? Anything new (living or not) added to the tank in the last month? When were the fish added? Any change in source water used for water changes? How about nitrites? (long shot, but worth a check)
 
beeZ, what are you finding in the way of exoskeletons? Does it look as though the shrimp are dying right after molting? I ask because that's what's wiped out two groups of RCS for me...one like yours I had had for a couple of months, they had molted several times but when they got to near adult size they just molted and croaked. The other batch just molted and died within a week of my getting them. :(

Are you finding 1 exoskeleton per 1 corpse of similar size?

I have no idea what caused it so regret am unable to help here. Only thing I can think to suggest is a call to your local water company to see if they have made any changes recently. Some places use different chemicals or different levels of them in winter than in warmer weather. Or there could have been a spill in the source waterway or something. Some change in your water that's not detectable to the senses or available home test kits is all I can think of.
 
I also have RCS and CRS from different sources dying one by one. I started from 30+, and now I have only a few left.. They bred well, but only a few offsprings would survive. I have no idea why they're dying off. I have an amano shrimp with the bunch, but this guy is still alive. I have moved them to another tank thinking it was the tank, and they're not dying off as rapidly anymore.
 
I notice a die off on the CRS when the nitrate level is at 10ppm.
 
pbmax said:
Any large temperature or PH swings? Any change in feeding lately? Anything new (living or not) added to the tank in the last month? When were the fish added? Any change in source water used for water changes? How about nitrites? (long shot, but worth a check)
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No PH or temp changes and I've been feeding the same pellets and algae wafer that they were getting before. They also seem to be eating fine. The fish and shrimp all existed in the old tank and were all added at around the same time. Source water is from my tap (city water) and gets treated with Prime before going into the tank. I am not aware of anything the city may have added to the supply but I can call and check.

I did not test nitrites. I will test tonight if I get a chance.

XanAvaloni said:
beeZ, what are you finding in the way of exoskeletons? Does it look as though the shrimp are dying right after molting? I ask because that's what's wiped out two groups of RCS for me...one like yours I had had for a couple of months, they had molted several times but when they got to near adult size they just molted and croaked. The other batch just molted and died within a week of my getting them. :(

Are you finding 1 exoskeleton per 1 corpse of similar size?

I have no idea what caused it so regret am unable to help here. Only thing I can think to suggest is a call to your local water company to see if they have made any changes recently. Some places use different chemicals or different levels of them in winter than in warmer weather. Or there could have been a spill in the source waterway or something. Some change in your water that's not detectable to the senses or available home test kits is all I can think of.
Click to expand...

Nothing notable with the exoskeletons except for the adult female that I found yesterday. I would say with certainty that there was a matching exoskeleton close by. I didn't notice this with the juvies that were dying.

Crispino Ramos said:
I notice a die off on the CRS when the nitrate level is at 10ppm.
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Interesting. I'll try to keep the nitrates low and see if that helps.

Thanks for the replies everyone. I'll keep an eye on the tank and post up any updates.
 
I've seen nitrates of 20 or more with no detriment to my RCS. Of course that doesn't necessarily mean anything for anyone but me. :)
 
what about overfeeding? I goofed up and left some old uneaten algae wafer in the tank for too long, and then found a nice big female (dang it!) keeled over next to it, like she ate some bad food and croaked. Coulda been something else, but made me suspicious. Seems like some are weaker, etc anyways. Good luck with the rest of them.
 
I don't think it's overfeeding. There are probably close to 60 shrimp in there plus the cories. The food is gone pretty fast.
 
do the cories not eat the baby shrimp? jw...
 
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