Amphipods turning orange?? (pics)

[killergoby]

The amphipods in my fuge have been turning orange the last 2 weeks, and now about 45% of the large adults are orange. I have no idea why this is happening. I searched around and found this article (https://www.atlasobscura.com/articles/amphipod-parasite-nutrient-pollution), but as I don't have any birds in my aquarium, the process cannot be identical for my situation. I would doubt I have a pollution issue, as all of my SPS and other corals are doing great (besides one acan I just received a day ago, but it'll bounce back once it's settled in. The refugium has xenia, Caulerpa racemosa peltata, Caulerpa ashmeadi, and one large anemone in it, as well as thousands of tigger pods, munnid isopods, flatworms, bristle worms, and these run-of-the-mill cockroach amphipods. I'm concerned about what's causing the change in amphipod color as every pod that enters the return pipe is consumed, usually by my anthias or cardinalfish. I even had a small amphipod eaten the other day by a turbinaria polyp immediately next to the return. I've attached some images of what these orange amphipods look like.

 

[Kris 2020]

Those are pumpkin spice amphipods, just in time for fall. Your fish will be so happy!
sorry, I couldn’t help it. And I don’t know enough about pods to answer your question. Bump it up!

 

[taricha]

as well as thousands of tigger pods,

I'm going to speculate that the amphipods are eating the Tigger pods and are themselves accumulating the carotenoids (astaxanthin) from the tigger pods.

 

[killergoby]

I'm going to speculate that the amphipods are eating the Tigger pods and are themselves accumulating the carotenoids (astaxanthin) from the tigger pods.

I have seen these larger amphipods consuming tigger pods, but the tigger pods themselves are less orange since introduction to my tank months ago. You're probably right on the color accumulation. This may also explain why the color change is mostly the largest amphipod individuals.

Anyone else ever have this occur?