HCA: Hermit Crab Association

I've seen some foods for sale on etsy and stuff marketed for hermit crabs and was just wondering if they actually are good for the crab, or if there are better/other, common household foods with the same nutrients?:

Green sand (what even is this?)
Astazanthin (is this just to help boost color or is there a niche nutrient in this?)

(I've googled most of the ones I was confused about, but these two left me more confused. The hca is honestly the best place for this kinda stuff, love you guys, I would be so lost without this forum)

Greensand comes off of the ocean floor. It is packed full of nutrients. The crabs LOVE it. I keep it in my tanks at all times. It is actually a mineral called Glauconite.

Astaxanthin is an algae that the crabs love. It is a color booster.

GotButterflies wrote: ↑

Mon Sep 02, 2019 9:24 pm

Greensand comes off of the ocean floor. It is packed full of nutrients. The crabs LOVE it. I keep it in my tanks at all times. It is actually a mineral called Glauconite.

Astaxanthin is an algae that the crabs love. It is a color booster.

I agree, my crabs devour this too quickly!