Killer shrimp

[Blue fish]

Sorry for the long post.
So I'm new here and just started a new tank after being out of the game for about 20 years. When buying my fish I thought back about fish I was familiar with from the past. So I got some black Mollies and Neon Tetras ( my favorite from the past ). After a few weeks I thought, "I should get some cleaner fish". Since I don't like plecostomus I opted for an emerald Cory. Then I seen a shrimp and thought that would be cool, so i got two.
After a few days I would only see one shrimp about. Then two days ago I seen one of my neons in distress swimming in one spot struggling to stay off the bottom. An hour later he was dead at the filter intake tube being munched on by the shrimp. Then the next day another neon was being eaten by the shrimp and one was missing. When i remove the cave the other neon came floating out, along with the shell of the missing shrimp. I removed the shrimp, needless to say. Until I put the shrimp in the tank the neons seemed to be thriving and healthy.
Has anyone had a problem like this? And shouldn't the pet store had told me about them being aggressive?

 

[Belltrain]

Do you know what kind of shrimp it was? How big where they? And when you say emerald Cory do you mean "emerald catfish" because they are different than Cory's. Did you only buy one?

 

[myswtsins]

In addition to the above questions...What size is the tank? When was it setup? Did you cycle it? Have you tested the water? How many fish were in the tank total?

Typical shrimp are not known to kill but they are excellent scavengers, they don't even have the proper equipment to kill with. Chances are that the fish and other shrimp died and the living shrimp cleaned up the mess.

 

[SnakeIce]

Unless it was a macrobrachium shrimp, those will hunt fish.

 

[FreshyFresh]

Welcome!
Sounds to me like the shrimp are doing what shrimp do. Eat dead or dying fish. You probably have a water quality issue that's effecting your fish. Like said above, did you cycle this tank? What is your water change frequency and volume? What are your water parameter readings in ppm for ammonia, nitrite and nitrate?

 

[FreshyFresh]

Sounds to me like the shrimp are doing what shrimp do. Eat dead or dying fish. You probably have a water quality issue that's effecting your fish. Like said above, did you cycle this tank? What is your water change frequency and volume? What are your water parameter readings in ppm for ammonia, nitrite and nitrate?

 

[Kaliska]

Sometimes the larger shrimp species do attack very small fish that are healthy but it's rare. It's common to lose some of the shrimp right after buying them from a pet store. They are very sensitive. The rotting shrimp could have messed with the water quality and weakened the other fish. Do you have a test kit for ammonia, nitrite, and nitrate? You could also have introduced illness with the shrimp and any water they came with. It's possible it's not related at all and your tank was just on it's way to having problems. If you haven't been testing the water to see how things have progressed and make sure it's cycled, the water you use is buffered with a stable ph, etc... a problem could have been developing for weeks or months.