Mysterious die-off
Posted: Mon Jun 13, 2016 9:38 am
As documented here viewtopic.php?f=2&t=5799&start=15#p38448 I had a pretty nice Ghost shrimp tank (a twenty gallon long) going until a few weeks ago. The shrimp were healthy, breeding, and had an amazing amount of colors for ghost shrimp. I was quite proud given they were the only shrimp aside from my supershrimp that I'd had breed.
Then I decided to get them some companions for a more diverse and interesting tank, cambarellus shufeldtii, the cajun dwarf crayfish. A group of twenty of these fairly inoffensive tiny crayfish I ordered off ebay.
For the first week or so everything was fine. The crayfish were a lovely addition with their varied markings and hilariously tough behaviors. I never saw any fighting between them and the shrimp either. But odd things started to happen. I found a couple shrimp dead on the underside of the glass top. They had apparently jumped out of the water and gotten stuck to the underside of the glass, drying out and dying there. Unusual but I didn't think much of it.
Then both the shrimp and crayfish started dying in the water. Some of them seemed to simply die, but most of them seemed to go through an odd period of decline at least partly linked to shedding. The crayfish would shed partially, get stuck in their sheds (usually around their legs) and die after a few days, or get out of their shed (usually losing most of their limbs in the process) and still die a few days later (or I would put them out of their misery as they were very alive but unable to walk and thus feed). The ghost shrimp would lose legs, become lethargic and eventually die. Eventually I lost all the shrimp.
I have never had any of my invertebrates experience shedding problems before so it can't be that the water isn't suitable for them. As further evidence, I have a crayfish in another tank that has lived for years without a problem.
During the die off and afterward there was no detectable ammonia any of the times I tested (I removed the bodies quickly) and very low (if any) detectable nitrates. Furthermore, the nerite snails in the tank have not had a problem at all. The large population of copepods survived just fine as well.
Perhaps most mysteriously, two of the dwarf crayfish are still alive, perfectly healthy and intact, and have likewise shed at least once just fine.
I have since then gotten a batch of eight or so ghost shrimp, but the same die off has occurred, I think only one is left. It may just be a coincidence as I know it is common for these shrimp to die soon after purchase as they are not kept in good conditions (since the pet store expects you to just feed them to other animals), but to have such mass and consistent mortality seems odd.
I have also gotten some dwarf frogs since then and they have had no issues in the tank either.
The only thing I can think of is that it is some kind of pathogen that the crayfish brought with them that also infected the shrimp and that the two surviving crayfish somehow are immune to it.
Basically I'm writing all this to see if anyone here might have an idea as to what happened.
Then I decided to get them some companions for a more diverse and interesting tank, cambarellus shufeldtii, the cajun dwarf crayfish. A group of twenty of these fairly inoffensive tiny crayfish I ordered off ebay.
For the first week or so everything was fine. The crayfish were a lovely addition with their varied markings and hilariously tough behaviors. I never saw any fighting between them and the shrimp either. But odd things started to happen. I found a couple shrimp dead on the underside of the glass top. They had apparently jumped out of the water and gotten stuck to the underside of the glass, drying out and dying there. Unusual but I didn't think much of it.
Then both the shrimp and crayfish started dying in the water. Some of them seemed to simply die, but most of them seemed to go through an odd period of decline at least partly linked to shedding. The crayfish would shed partially, get stuck in their sheds (usually around their legs) and die after a few days, or get out of their shed (usually losing most of their limbs in the process) and still die a few days later (or I would put them out of their misery as they were very alive but unable to walk and thus feed). The ghost shrimp would lose legs, become lethargic and eventually die. Eventually I lost all the shrimp.
I have never had any of my invertebrates experience shedding problems before so it can't be that the water isn't suitable for them. As further evidence, I have a crayfish in another tank that has lived for years without a problem.
During the die off and afterward there was no detectable ammonia any of the times I tested (I removed the bodies quickly) and very low (if any) detectable nitrates. Furthermore, the nerite snails in the tank have not had a problem at all. The large population of copepods survived just fine as well.
Perhaps most mysteriously, two of the dwarf crayfish are still alive, perfectly healthy and intact, and have likewise shed at least once just fine.
I have since then gotten a batch of eight or so ghost shrimp, but the same die off has occurred, I think only one is left. It may just be a coincidence as I know it is common for these shrimp to die soon after purchase as they are not kept in good conditions (since the pet store expects you to just feed them to other animals), but to have such mass and consistent mortality seems odd.
I have also gotten some dwarf frogs since then and they have had no issues in the tank either.
The only thing I can think of is that it is some kind of pathogen that the crayfish brought with them that also infected the shrimp and that the two surviving crayfish somehow are immune to it.
Basically I'm writing all this to see if anyone here might have an idea as to what happened.