shrimp question

I'm new to freshwater shrimp and I was hoping someone could answer a question for me. I have about 10 rcs and 5 crs in a 5 gallon planted tank along with a few Vietnamese white clouds (smaller than the normal white clouds, max 1"). The tank is cycled (Biospira, squeezings from media from my well-established tank, readings cleared up 3 weeks ago) and the parameters (as of 5 minutes ago) are ammo 0, trites 0, trates 0, ph 6.6, temp 74. The shrimp joined the tank about a week ago and have been doing great as far as I can tell - very active, eating, showing great color. I've been feeding cyclops and bloodworms to the fish (frozen) every day and a tiny piece of algae wafer for the shrimp every other day. (Shirakura shrimp food is on it's way in the mail). Oh, and the tank has never had copper in it and I haven't been fertilizing other than a couple of drops of Flourish excel.

This morning there was a dead shrimp. I'm pretty sure it's a rcs. It looked fine except instead of being clearish it was opaque and on it's side. It's not a molt 'cause it looks pretty solid, unlike the 2 molts I've seen so far. Is it because I'm not feeding them the right food? Is the temp too high? Any thoughts from you more experienced shrimp keepers out there? I guess it could have just been an old shrimp or something, but I just want to make sure before I lose any others.

Secondary question: I keep trying to get the dead shrimp out but the other rcs are pretty possessive of their newly found "meal" and keep pulling it away into the plants or underneath the driftwood. Should I keep at it until I get it out or should I let them eat it?

The nitrates have never gone higher than 5 ppm, but usually is 0. It's pretty densely planted, but it's really the floating watersprite that's functioning as the nitrate sponge (and growing like nuts - I have to thin it out at least once a week). I'm using the API liquid tests.

I haven't starting dosing fertilizer 'cause I use Flourish products in my other tank and I know Flourish has small amounts of copper in it. I just picked up a bottle of Kent's Pro-Plant 'cause it doesn't have copper but I haven't tried it yet so it can't be the fertilizer. I do dose Flourish Excel about twice a week, but that doesn't contain copper either (at least according to the label) and I dose pretty lightly just to be safe.

Maybe it was just old age - I really can't think of anything else that could have caused it... Any other ideas? Thanks!

Well, no more deaths yet so for now I'm thinking that it was an isolated incident. I think it was a she, and she was one of the largest that I had so I'm hoping it was just residual shipping stress - as of today I've had them for a week. I've gotta say it was a little bit disconcerting when I pulled the shrimp out of my tank - aside from it's teeny size, it looked exactly like a peel 'n' eat shrimp off of an appetizer plate! Kinda gave me a taste for seafood...