A worried look

Young hairy hermit, checking out the camera.

"What does that big eye belong to? Will it eat me?"

Even in a protected tank, with no predators, life can be difficult. This hermit is missing most of one antenna. The other is fine, just bent back behind his shell.

Mostly, the hermits and crabs get along peacefully, but when it's feeding time, tempers can flare. They snatch at the food that another has captured; sometimes a hermit retires into his shell, carrying the shrimp pellet with him. Another of the hermits, or maybe a crab, will spend several minutes poking inside the shell, trying to steal the food. Never mind that the thief is probably straddling two or three pellets, just as fresh. No, he wants that one! Forbidden fruit always tastes better.

Or a hermit will chase another across the tank, grabbing at legs, antennae, shells, trying to slow down the other to take away that delicious piece of shrimp. So one of the crabs is missing her back leg. Another of the hermits has lost two legs on one side.

Never mind; they manage fine with only three or four legs and one antenna. The food comes down regularly; they're in no danger of starving. Or of being eaten by a gull because they didn't hide fast enough. Here there are no gulls.

(This hermit's shell has grown a crop of green algae and it looks as if a tribe of copepods is feeding on it.)

Talented half dollar

The little sand dollar in my aquarium (more like a 50-cent piece) wanders all over the tank, usually underneath the sand and shells, but sometimes coming out in the open for a brief look around.

He moves more quickly than I would expect, travelling only on spines a couple of millimetres long. When I clean the tank, I remove him carefully so as not to break off those fragile spines, and then put him back on the surface of the sand at the front of the tank when I'm done. Within minutes, he's upended himself, and is burrowing back down out of sight.

Sandy, feeding. Much larger than life.

A few days ago, he showed up right by the glass wall, and I got a video of him feeding and "walking". Once again, I was amazed at his talents; with those hair-like tube feet, he picks up fat grains of sand, lifts them to the mouth to check them for edibles, then drops them.

And he manages to walk and chew sand at the same time. Smart critter!

Here's the video. It helps to watch it on the full screen.