My great ugly workhorse.
I don't know why, but my older amanos keep changing colors when they molt- used to be more yellow, then orangish, some are almost brick red now. Newer ones I got recently are translucent and spotted like JonRon's. (Are these not amanos?)
If you have driftwood inside your Aquarium, your Amano Shrimp could be eating algae of it, causing the Change of Color.
Furthermore, a Quote from petshrimp.com
"When shrimp are very sick and almost dying they change their colors...one of the more common sick colors is reddish".
Lastly, this so called Amano Shrimp could actually be a bamboo shrimp(Atyopsis moluccensis)
The bamboo Shrimp is a filter feeder and will sit where there's good current and filter feed from there. If the tank water is too clean the shrimp can starve, you can crumble food such as plec wafers into the current and the shrimp will feed from the particles it catches. If you keep a few Amano Shrimp in the tank, the females should provide a steady stream of planktonic larvae which the Wood Shrimp will happily consume as they float by in the stream. A ratio of about 9 female Amano's seems to keep 3 adult Wood shrimp from picking the floor in a clean aquarium. The Wood Shrimp is an attractive shrimp with thin horizontal red lines running down the body and a thick white stripe down the spine.
I hope this will sum up your concerns about your Shrimp.