Can mercury be a concern?

[Chester08]

I work in a LFS and have a customer with a puzzling problem. He has a 5ga nano tank that he's had set up for over a year. The tank was doing fantastic, with hermits and snails and a few small gobies.

A few months ago, his kids talked him into putting a few crabs they grabbed out of the water from New York state into the tank.

Within a day, he said the tank turned cloudy and white, and the following morning, everything in the tank (except the crabs) was dead.

He replaced everything except the rock in the tank, and said he let the rock air dry, then re-soaked in fresh water. He's since added a few nassarius snails, a few red-leg hermits and a pygmy angel. They're doing fine.

However, he's tried three cleaner shrimp, and every one, within minutes of being in the tank, has died.

He drip acclimates the shrimp, so it shouldn't be the acclimation process. He says all his parameters test fine, including copper. (I'm trying to get him to bring me a water sample so I can see what "fine" is).

Anyone have any idea why these shrimp are dying so fast? Is it possible for these NY crabs to have introduced mercury into the tank? I'm at a complete loss as to what is killing these poor guys.

Thanks in advance for any thoughts/help/theories!

-Erica

 

[Tayler]

dont have an answer about the shrimp but a pygmy angel seems a little big for a 5 gallon.

 

[Chester08]

It is....there's not much NOT too big for a 5ga, but tell him that when he has two screaming kids saying "Daddy daddy daddy I want THAT one"

 

[Fat Man]

Any mercury would be locked within the crabs' bodies. He could of introduced some pathogen with the crabs. A 5gal is such a small volume of water almost anything could put it out of whack.