In an attempt to explain some of the blue colored shrimp being sold in the hobby recently an experienced shrimp keeper came up with the following hypothesis:
“What differentiates most of our aquariums from the actual streams, creeks, and puddles our shrimp live in naturally? Heaters of course, DUH. What occurs naturally over the year in most places? Seasons with temperature changes… DUH.
What produces intense dark coloration in many shrimp that last for life? Cold water.
What have I done this with? Cherry shrimp, repeatedly, and never made the comparison to the purple toned cherries I’ve had in the past to blueberry shrimp. This is also because I believe that each year the seasonal changes are required to enforce the color change.”
My Thoughts:
The Neocaridina heteropoda (wild form of Red Cherry Shrimp) comes from South China and Taiwan. This area is Sub-Tropical and does not have seasons in the way that most American States have. The average highest air temperature is right at 90 and the lowest is just above 50.
The 50 degree temperatures are only experienced late at night and do not last long. This climate leads to fairly stable water temperatures with a summer average and winter average water temperatures only being about 15 degrees different.
None of my aquariums have heaters in them. I have the fortune to live in Central Florida where my average temperatures are very similar to that of Taiwan. It gets a little hotter here and also a little cooler, but because of this stable temperature range I have never had a need for aquarium heaters.
My aquariums tend to run 10-15 degrees cooler in the winter than in the summer (just like the air temps in my house). I have never noticed any difference in color in any of my shrimp during winter.
What causes the colors?
I am a firm believer that any shrimp that is caught in the wild that has a blue color that does not pass to its F1 offspring is caused by a food source available in the wild that is not replicated in captivity.
What are your thoughts?