(They're incredibly efficient diggers. They scramble deep under a big rock, sideways, and a minute later slide out again, pushing a load of sand with their claws. Back in they go, and out with more sand, pushing it up the slope until it crests the rise and doesn't slide back. I have seen them create a pile a couple of inches high overnight. They don't stop for coffee breaks.)
They come out of their tunnels and burrows after dark, and sit waiting for me to arrive with food, a piece of dried minnow, crumbled into bite-sized pieces. (Crab and hermit bite-size, not mine.) I don't know if they would prefer another feeding time, but at night is when the big polychaete worms come out, too; I love to watch them creep out of their holes, ever so slowly, sniffing here and there, this way and that. Then, suddenly, they grab a choice bit of fish out of a crabs' pincers and whip it down into the sand before the crab can say, "Stop, thief!"
When I clean the tank, I fish them out with my hand, and put them in a bowl with the hermits and snails. They're ok with that. Afterwards, they go back to their digging, repairing the comfortable burrows that I filled with sand. No worse that the incoming tide would have done; that's life.
With that background, I thought that they really wouldn't mind a visit to my new underwater photo studio; they know me, they can trust me. I've never hurt them yet.
I was wrong. They panicked. They scrabbled around frantically, trying to hide under each other, under the stones, against the opposite side of wherever the camera was.
The baby, feeling safe for the moment.
Spots, watching me over the back of his head. That's Snowflake underneath him, and a piece of fish at his back feet. I thought that would placate them. It didn't.
Snowflake and Rusty.
Five minutes, maybe ten. The crabs were trying to burrow underneath my glass divider, tossing stones behind them. I gave up, and replaced them in the aquarium; they scuttled for cover. The next day, they had recovered, and were glaring at me through their glass wall. This wall is good; it's familiar. Even if it's as see-through as the other.
I think the first three, Baby, Spots, and Snowflake are green shore crabs, Hemigrapsus oregonensis. The colour and patterns vary, especially in juveniles, but the legs are hairy. Even the littlest one shows a bit of hair; look closely. Rusty, the dark red one, may be a purple shore crab, Hemigrapsus nudus (nude or naked); these are missing the hair. In the right light, I can see the purple spots on his pincers.