Planted Tank Enthusiast
Join Date: Dec 2010
Location: San Francisco, CA U
Cherries are pretty bomb-proof. To give you an example of just how bomb-proof, I once yanked some excess Xmass moss from my main tank and through it in a cereal bowl with some water. It stayed there for 2 months, and I never touched except to occasionally put a a table spoon of water in the bowl to top off from evaporation.
When I finally went to sell this moss (which was still green and healthy btw), I noticed 3 juvie cherry shrimps still alive and seemingly doing fine.
That said, there are steps you can take to prevent what happened to you, especially if you are dosing CO2 in any form.
First, use aeration at night when your lights go off via an air pump and airstone. This will counter-balance the CO2 that is being given off by the CO2 during the day, and greatly increase your shrimps health at night, diminishing chances for sudden death due to toxicity.
Also, make a small investment in a GH and KH test, and make sure they are within normal range. For cherries, honesty they can survive through almost anything, but for other species, like CRS for example, you'll want the KH very low (2 or less), and the GH in the 3 to 6 range.
Also, make sure you are washing your hands before they ever hit your tank water. Some small remnant on your hands could be enough to contaminate water.