Encyclopedia Brown and the Mystery of the Color-changing Crystal Reds

[tolstoy21]

I'm probably dating myself here with the reference to 'Encyclopedia Brown', but anyway . . . .

I threw some crystal red shrimp in my community tank just for the heck of it about a year ago. Today I'm emptying the tank out and am noticing something I have never seen before . . . . my shrimp have changed color!

When I put these shrimp in, they were your standard very white and red shrimp, like the one 'before' example pic I'm including along with the pics of these shrimp today.

I'll admit that I did notice these slowly transforming when they occasionally ventured out from the dense planting of anubias, but I didn't notice the extent until I started emptying the tank out.

As you can see in the pictures, they have lost most of their white pigmentation, but have acquired a lot more red -- kind of like that are transforming into 'super red' crystals. These shrimp have never bred in this aquarium to my knowledge so these are the original shrimp and not the result of selective breeding.

Does anyone know if this could be caused by water parameters? These specific shrimp have been living in tap water and eating fish food and whatever else they could find in my aquarium. 

Weird, huh? Or is this totally normal?

[Odd Duck]

If it’s been a year there’s a decent chance there was some breeding.  Lifespan on these guys is 12-24 months.  There could be color change, too, as many shrimp’s color will depend with age, but that looks like a breeding color shift to me.  I’m certainly NOT a shrimp expert, but my limited experience with shrimp makes me lean toward gene mix vs. individual color changes.

[tolstoy21]

On 7/29/2023 at 6:19 PM, Odd Duck said:

If it’s been a year there’s a decent chance there was some breeding.  Lifespan on these guys is 12-24 months.  There could be color change, too, as many shrimp’s color will depend with age, but that looks like a breeding color shift to me.  I’m certainly NOT a shrimp expert, but my limited experience with shrimp makes me lean toward gene mix vs. individual color changes.

These shrimp have never successfully bred in my tap water, though there are about 1 bazillion Orange Rili's in the tank. When I emptied the tank, I found a handful of full adult caridinas, but no juveniles, no shrimplets, etc.--nothing but full-sized adults--which leads me to believe these are the original dozen or so I threw in.

I've bred this specific line of CRS for maybe 5 or 6 or more years (I'm losing tracking of time), and their color never changes away from a pretty solid red and white.

This is the first time I've seen any of the shrimp from this line be all red like that. I have never seen a single shrimp look close to how these look close, and I've bred and sold probably a few thousand of these over the years. To go from what are typically S - SSS+ shrimp to super red in the course of one or two generations seems unlikely in my experience selective breeding these.

I put the shrimp back in with their original colony. I'm curious to see if their coloration/pigmentation shifts back.

My bet is that this odd pigmentation was influenced by environmental factors, or food. The water they were in is close to 400 TDS, and as far as I've read, CRS should croak in that water (despite my empirical evidence that suggests otherwise!). Actually, my water is KH 0/Gh 9ish, and probably has a bunch of other crap in it from my well.

Anyway those are my thoughts on this whole mystery.

Edited July 29, 2023 by tolstoy21

[Odd Duck]

Very interesting!  Keep us posted on what they do!