Can Ghost Shrimp kill Corys??

I have a 46g bowfront with a bunch of livebearers and (until 2 days ago) 3 cory cats. The water is 33% changed weekly, and has 0 ammonia and nitrite, and 20ppm nitrate. The corys have been fine for months. I purchased a few ghost shrimp to try to help out with some cleaning of the tank (e.g. hair algae) and 5 cardinal tetras to try to brighten up the bottom 1/3rd of the tank. The cardinals all died within a few days - I have high pH, and that probably did it. 48 hours later, overnight, all three corys died. There are no signs of any distress from any of the mollies or guppies or the lonely painted glass tetra in the tank.

Is it possible that somehow the ghost shrimp killed the corys??

 

Nah it definitely wasn't that. Out of curiosity, how high is "high"?

 

Maybe the cardinals brought a disease with them? Or maybe they are actually wisker shrimp, I've heard that wiskers can actually kill fish.

 

Nah it definitely wasn't that. Out of curiosity, how high is "high"?

7.6-7.8. I tried drip acclimating the neons (LFS recommended it) and it failed miserably.

Maybe the cardinals brought a disease with them? Or maybe they are actually wisker shrimp, I've heard that wiskers can actually kill fish.

It could be disease, but it seemed odd that all three went from fine to dead within 8 hours. I blamed the shrimp because when I found the fish I saw one sitting on the shrimp presumably eating...

 

7.6-7.8. I tried drip acclimating the neons (LFS recommended it) and it failed miserably.

It could be disease, but it seemed odd that all three went from fine to dead within 8 hours. I blamed the shrimp because when I found the fish I saw one sitting on the shrimp presumably eating...

Can you get pictures of the shrimp?

 

Can you get pictures of the shrimp?

 

Some larger shrimp may be able to kill very small fish, especially fry, but they are not going to bother with larger fish. However, shrimp and snails are scavengers that will readily descent on a dead fish. If you had the corys for several months, they would be too big to be attacked by the shrimp. However, if they died due to another issue, they would soon become shrimp food.

Guppies and mollies can easily adapt to hard, alkaline water. Corys and cardinals normally come from South American waters where the water is softer and more acidic, although many are tank raised.

By any chance, were the ghost shrimp you purchased the cheap shrimp sold as feeder shrimp? If so, they often introduce pathogens into the aquarium.

When you add new fish (or shrimp) to a tank, it is a good idea to quarantine them first to make sure they are healthy and do not infect your existing fish. It sounds like you did not take that precaution.