Magical Disappearing Cherry Shrimp

Gemtrox42

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I have two tanks, the layouts of which are -

10gal, heavily planted, driftwood and cholla wood, decorative caves, w/ 2 Honey Gourami, 1 Clown Pleco, and 4 cherry shrimp I placed in the tank within the last month

30gal, lightly planted, with lots of driftwood and duckweed, w/ 14 cardinal tetra, 5 dwarf corys, more assassin snail babies than I can count, and numerous cherry shrimp that have had several generations of babies

My water parameters are good, but if it really sounds like a water issue I can provide them. As there are multiple other fish in each tank, I am unsure if my shrimp get the food I drop in for them (Hikari Shrimp Pellets). The shrimp seem to die at random intervals, and not all at once.

Now to the timeline:

I have been keeping cherry shrimp in my 30 gal for 9 months now. First I bought 6, 3 of which disappeared, 1 I accidentally killed and 2 I found dead. The next round of shrimp, I got 6 again. This time 4 disappeared again, leaving one female and one male. The female had at least 2 rounds of babies, until she disappeared along with the male. By this point, I had countless shrimp in my 30 gal and I bought 4 for my 10 gal. Slowly but surely, my 30 gal has gone from countless shrimp to a handful, and as of today all 4 shrimp in my 10 gallon have disappeared. I checked the 10 gal and filter top to bottom for shrimp, alive or otherwise, and came up empty handed.

So that's the story. I will make an ongoing list of possible explanations, ranked by plausibility if necessary, to help me narrow down the possibilities. Please feel free to suggest removals or additions to the list, as well as providing any other information or asking questions that could help.

  • Shrimp are eaten by fish (plecos and corys, or cardinals and gourami?)
  • Shrimp are being poisoned by something in my tank water/food (Water chemistry?)
  • Shrimp are dying from disease (Which?)
  • Shrimp aren't getting enough food
  • Shrimp die from failed molts
  • Shrimp aren't getting necessary elements/getting too many
  • Shrimp are all really good at hiding
 
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Circus

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Are there any symptoms? Are they odd looking after they die? Do you have copper pipes, or a lot of copper in your water?
 

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  • Shrimp are eaten by fish (plecos and corys, or cardinals and gourami?)
  • Shrimp are being poisoned by something in my tank water/food
  • Shrimp aren't getting enough food
  • Shrimp die from failed molts
  • Shrimp aren't getting necessary elements/getting too many
  • Shrimp are all really good at hiding
Any pictures of the remaining shrimp?

Cardinal tetras might eat cherry shrimp if the tetras are hungry. However, if you are feeding the fish daily, they shouldn't bother the shrimp. The other fish might eat the shrimp if they die but won't hunt them down and eat them.

It's unlikely to be a poison if they bred a few times. However, poor water quality will kill them.
Have you checked the ammonia, nitrite, nitrate and pH of the tank water?

It's unlikely they aren't getting enough food. Unlike mammals that use most of the food they eat to keep warm, most fish and shrimp take their body temperature from the surrounding water. This means any food they eat is used for growth and movement. Subsequently, fish and shrimp can go for weeks or even months without food. If you are feeding the fish & shrimp each day, and you have live plants in the tank, there should be plenty of food for them.

Losing 1 or 2 shrimp to a failed molt is possible but not losing lots of them. If you are losing shrimp regularly, they are either being eaten or dying from something. There are several diseases that kill shrimp and are hard to see. The most common one is spironucleus, which causes the muscle tissue to turn cream/ white and the shrimp eventually dies. If fish or shrimp eat the infected tissue, they get the disease and die a month or so later. This can be treated with salt (2 heaped tablespoons per 20 litres). Keep salt in the tank for 4 weeks.

Nutrients and minerals shouldn't be an issue if they are fed a varied diet and have plants in the tank. If you are using reverse osmosis (R/O) water, it might be lack of minerals, but if the GH of the water is above 50ppm, they should be fine.
 
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Gemtrox42

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Are there any symptoms? Are they odd looking after they die? Do you have copper pipes, or a lot of copper in your water?
It's hard for me to establish any symptoms or what they look like upon death because I haven't found any dead in over 4 months. From what I remember of the two that died, one was hanging upside down off the duckweed on the surface then suddenly dropped to the bottom and stopped moving. I left it in an enclosure in the tank for 24 hours to prevent it from being eaten and to make sure it was really dead. As far as I remember, both looked relatively normal.

I don't know how to tell if I have copper in my water. Is there a test that can establish that? And since you asked, im assuming its a yes, but do these instances sound like copper poisoning to you?
 
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Gemtrox42

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Any pictures of the remaining shrimp?
I can't get pictures that would be of any help. All the remaining shrimp are very lightly colored, almost see-through in appearance, and my camera won't focus on them.
Cardinal tetras might eat cherry shrimp if the tetras are hungry. However, if you are feeding the fish daily, they shouldn't bother the shrimp. The other fish might eat the shrimp if they die but won't hunt them down and eat them.
Does that include the assassin snails? Though it wouldn't explain the missing shrimp in my 10gal, I'd like to establish it.
It's unlikely to be a poison if they bred a few times. However, poor water quality will kill them.
Have you checked the ammonia, nitrite, nitrate and pH of the tank water?
0, 0, <5, and 7.3
Losing 1 or 2 shrimp to a failed molt is possible but not losing lots of them. If you are losing shrimp regularly, they are either being eaten or dying from something. There are several diseases that kill shrimp and are hard to see. The most common one is spironucleus, which causes the muscle tissue to turn cream/ white and the shrimp eventually dies. If fish or shrimp eat the infected tissue, they get the disease and die a month or so later. This can be treated with salt (2 heaped tablespoons per 20 litres). Keep salt in the tank for 4 weeks.
Since this has been going on for well over 6 months and I haven't lost any fish along with the shrimp, can we rule this out as a possibility?
Nutrients and minerals shouldn't be an issue if they are fed a varied diet and have plants in the tank. If you are using reverse osmosis (R/O) water, it might be lack of minerals, but if the GH of the water is above 50ppm, they should be fine.
gH is about 200ppm.
 

Circus

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I don't know that there are any specific symptoms for copper poisoning. I know that API does have a test kit for it though. A call to your local water provider might give you some answers. You local petstore might offer testing, if they have it in their kits. You can call and ask.
 
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Gemtrox42

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Update for anyone who cares - I found baby shrimp a few days ago, so apparently the adults were just hiding really well! Today I saw one of the 4 adults as well. While I still find it strange that some seem to disappear forever, it doesn't look like a mass die-off is occuring. Thanks for all your suggestions.
 

Calistmo

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Check around the tank for jumpers. I moved my stand last week and found about 10 dried up shrimp behind it.
 

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