In a snowy underwater jungle

Every few days I pull up a stool and aim the camera at the community in my little aquarium. Yesterday, I took over 100 shots; two were usable, with a possible third to be processed. Par for the course.

I love it when one hermit goes for a walk on a blade of eelgrass, above the jungle below.

Small hermit, running, on waving eelgrass, halfway across the tank, but near the light. And the water is nearly clear up here. Auto lighting, auto noise filter. Piece of cake!

Most of the crab and hermit crab activity, however, goes on down on the floor, amid scraps of seaweeds, worms, copepods, amphipods, snails, waving antennae, limpet poop, dancing sand grains, rolling stones, broken shells, waving anemone and barnacle tentacles.

And algae. Algae covers everything, including the glass I'm shooting through. No matter how I scrub it, there's always some there, caught in the scratches on the glass. The hermits and crabs are responsible for these scratches; they're always banging about with the sharp edges of their shells, or piling up sand against the glass, and then scraping it away, or trying to climb the unclimbable.

And the water is full of blowing "snow", the crumbs of food tossed out by the crabs, (messy eaters), copepods and air bubbles, bits of torn seaweed, shreds of discarded hermit molts, more limpet poop, oyster spits, more fragments of algae. The crabs and hermits are happy in clear water, but the anemones (orange-striped green, burrowing, pink-tipped green, and plumose in this tank) love this nutritious snow soup.

The camera doesn't. I can train my eye not to see it, but the camera notices every little copepod antenna and every rotting spot on the seaweed.

So here's a hermit (and a bit of a second hermit) in her usual habitat, just the way she likes it, the way I would find their community on the shore (except there, if I get down to their level, they all up and leave):

Grainy hand hermit, Pagurus granosimanus, with a shell she's rolling around. It's too small for a new outfit, so maybe she's just playing. She has lost most of one red antenna; probably in an argument over a scrap of food.

I had to clean up the background, delete quite a bit of glass algae and a blurry anemone, and adjust the light just to make the hermit visible in the mess. Imagine algae spots and swimming tinies all over.

Down in the left corner is a swarm of copepods. The snail shell at the right is vacant; soon one of the growing hermits will claim it. Some of the limpet poop is visible to the right of that blue stone.

The seaweeds are green sea lettuce, well used, a dark red blade algae, some holey kelp blades; the hermits have been chomping on this all week. The yellow edges are where the red algae is dead and flaking off. I could remove this, for the look of it, but the hermits love to eat it, so it stays. Both the hermit's shell and the empty snail shell are coated with thick green algae. The yellow stuff in back is the kelp that came with its holdfast last week. I just checked; there are four hermits working on this at the moment.

One of my crabs is very pregnant. I've been trying to get a photo: she's not cooperating. One of these days; now that the days outside are so short, I'll have more time to wait for her.

Pod critters

I found a container of old shells, imported from who knows where, in a thrift shop. My hermits always need shells, and a bit of variety is always welcome (from a very human point of view). I brought home the shells, washed them thoroughly to remove any dust or foreign substances, soaked them overnight, boiled them in several changes of water, just to make sure, and added a few to the aquarium.

The hermits liked three of them. The rest, they rolled over a few times, then abandoned. Not the right shape, not the right taste, maybe just unfamiliar; whatever the reason, the ones I thought were prettiest were just not good enough.

Nothing goes to waste. Several orange-striped green anemones promptly moved into the unpopular shells, and an amphipod claimed another.

Cozy hiding place.

Amphipod, belly up. Feeling safe in there, it seems. And another five, in more usual poses.

These were down at the bottom of the tank, where the glass is much scratched from shelly critters trying to climb it. I blurred out or erased as many of the scratches as I could, without touching any of the copepods. There are dozens, small and smaller, some so pale they are almost invisible against the white shell.

The copepods trailing a second section are females with their egg masses. Some of these egg masses are definitely baby blue, others are white. But all the copepods have the one red eye, sometimes the only thing visible.

The orangey rods are probably limpet poop.

Limpet, snails, etc.

A few August aquarium critter shots: the residents who wander close to the glass, where bubbles and amphipods and bits of seaweed don't get in the way.

LImpet. The yellowish bits are limpet poop.

Limpets are built like snails; because they have retreated into a shell that opens only on one side or one end (snails), their anatomy has to be twisted away from the "normal" head to tail shape of other animals. For example, they have two kidneys, as do we. But the left one is tiny, because it just wouldn't fit otherwise. On the exposed bottom of a limpet, we see the mouth, two tentacles, with their eyes, the big foot, with the gills laid alongside. (Not visible in this photo.) And the anus is up near the head. Which could be a problem.

The anus of most molluscs and indeed many animals is located far from the head. In limpets and most gastropods, however, the evolutionary torsion which took place and allowed the gastropods to have a shell into which they could completely withdraw has caused the anus to be located near the head. Used food would quickly foul the nuchal cavity unless it was firmly compacted prior to being excreted. (Wikipedia) (My emphasis. "Nuchal" means near the neck.)

One of the tinier hermit crabs. The eelgrass is about 1/4 inch wide; half its width is visible here. So the hermit, shell and all, is about 3/8 of an inch long.

Channelled dogwinkle, Nucella canaliculata. It eats barnacles, prefers mussels. I don't bring many mussels home for them, though; they (the mussels) trap and kill my hermits.

Channelled dogwinkle finishing off a stonefull of barnacles. There is one still alive, still cheerfully trolling for supper, at the bottom right. Sometimes I feel sorry for them.

Bejewelled (or at least, be-sanded) Japanese nassa, Nasarius fraterculus. The fine sand must be stuck to the algae growing on the shell. Average sand grains beneath it: these are not stones.

Knobbly column of a pink-tipped green anemone. The neighbours are a limpet, a couple of Asian mud snails (invasive Batillaria), a hermit, and another pink and green anemone. There are 11 of these in the tank now; they keep cloning themselves.

And the chiton is still on his moon snail shell.

Srevotfel, redux

A month's worth of aquarium pix; the odd shots taken while I was stalking something else.

One of the smaller hairy hermits, wearing a live barnacle on his shell. On Barnacle Mountain.

Young proliferating anemone. They live on their mother's column until they feel ready to leave home, then detach and float off to a new site. There are about half a dozen scattered around the tank, and another few still clinging to Mom.

Flatworm on the wall, carrying a small snail. Supper's cooking!

Making a snail taco.

A mouthful of snail meat. The shell has been dropped. A new outfit for a small hermit!

One of my tiniest hermits. These are sometimes orange, sometimes dark brown and white. I don't think they're hairies; they don't get much bigger than this.

Face shot of a small red shrimp

Snowy, again. Growing up, getting braver. His eyes are green now, his body a bit speckled.

Snowy molted. And I found his carapace before it crumbled.

I've been trying to determine his species; it's difficult, him being so small and so elusive. So I was glad to get an entire carapace, to see the shape and count the teeth. And I'm still not quite sure, but I think he's a baby red rock crab.

The carapace of adults is deep brick red in color and has 5 teeth that protrude anteriorly between the eyes.  Nine teeth that line the edge of the carapace lateral to each eye have a somewhat fluted appearance, like pie crust.  Carapace shape has been described as being fan shaped or shaped like the letter “D”.  The pinchers have black tips.  Juvenile red rock crabs are quite variable in carapace color and pattern, the patterns sometimes being quite exotic. (WSU BW)

5 teeth between the eyes: check.
9 teeth along the edge: probably; hard to see clearly.
Fan-shaped carapace: check. It's bumpy, too; the Dungeness crab has a smooth carapace.
Black-tipped pincers: looks like that's where he's going; there's a faint purplish tinge to the tips now.

Small bubble shell, wearing green algae.

Limpet, pooping.

Every batch of eelgrass comes home with a fair number of limpets, mostly quite small. They trundle about, cleaning the eelgrass, cleaning the walls, sometimes sleeping for a day or two. As long as they stay stuck to anything, they do well; if at any time they lose their grip and fall to the sand, they are eaten within minutes. The hermits hold them in one pincer, open side up, like a bowl of stew, picking out the meat with the other pincer.

With a sea star or two in the tank, things change; only on the eelgrass are they safe. Wherever the sea star can get a solid grip, he can rip the limpet away from his base. This large one (above) only lasted a few days.

Another mystery solved - I think

Last December, looking at the limpets on the walls of my aquarium, I noticed a long, worm-like thing wrapped around its neck. I couldn't identify it; nor could my helpful commenters.

Original photo, from "No end to mysteries".

And then, a month later, I posted a second "worm", which turned out, instead to be a limpet's gill.

Limpet gill, from "The mystery deepens", and "One down, one to go"

Since then, I've been watching limpets closely. I've seen the gills many times, but there's still that long neck-scarf "worm" to identify.

I think I've found it!

That's no worm!

I think it's limpet poop!

Do you agree?