Aquarium Update 7

Long time no post, just been too busy! The aquarium is doing reasonably well at the moment, especially considering the fact that I have not done any water changes since the last update and I have added a bunch of new organisms. I have added two Beadlet anemones Actinia equina. They are a dullish brown (except for a nice blue band around the base); I have not found the bright red or green individuals yet. Very similar but more striking are Strawberry anemones Actinia fragacea of which I have collected three. They are voracious, I could easily feed them a shrimp a day. The same goes for the Sea scorpion. I am afraid of sticking my hand in now as it comes after me! Time to let this buddy go. This will also give me the opportunity to add some other things such as squat lobsters.IMG_4825I have taken a break from experimenting with seaweeds and am focusing on anemones instead. I have added a bunch of small Plumose anemones Metridium senile that I scraped of the side of a pontoon. Weird fellas, they can fill up with water to be quite large, or just reduce to a crumpled little pancake. I have four white ones; I could only find very small ones of the orange variety and these were all devoured by Cushion stars (interesting). I’d like to have a large orange one as well, but I have to wait half a year until I can go diving again (they are very common in deeper water).

IMG_4812On the sheltered, silty shore of Flushing I found two small anemones attached to rock and half buried in the maerl sand. My excellent Seasearch Sea Anemones and Corals guide told me they were a Daisy anemone Cereus pedunculatus (uniform greay with many very short tentacles) and a Red speckled anemone Anthopleura balli (purplish and speckled, for a better picture of a different colour variant see this old post). Both quickly half buried/half nestled themselves under a rock so only the tentacles and the mouth are visible. They take pieces of shrimp and so hopefully they’ll be able to grow; these species should reach a decent size: IMG_4721

IMG_4729My friend marine biologist Chris gave me a snakelocks anemone that he had cured from its symbiotic algae. A very cool, bright white individual but it has returned to its original purplish colour so it must have taken up symbionts again. The snakelocks I already had, grew big, split into two and grew some more. Interestingly, one of the individuals seems to be turning from the green- to the purple colour variety:IMG_4828So six anemone species in all. I would really like to have some Dahlia anemones, they are very colourful, large, and not uncommon (old pic here). I need to go anemone hunting at a good low tide soon (I have not been out in ages).

I had the Chryseminia seaweed growing attached to the Tunze for a while and it worked OK, but it looks a bit messy and so I will remove it. However, I see that little Chryseminia plants have started to grow from the rock in many places (see top picture). I have to give the glass a weekly clean (with a tooth brush) and the rocks have turned a bit too greenish recently. I have noticed however that near the Snakelocks anemones, tufts of filamentous algae have appeared, as the grazers do not want to come too close to their tentacles (this reminds me of a work by an ecologist friend of mine who studies how seedlings can be protected from grazers when growing close to thorny shrubs, I’ll have to tell him of this observation!).

There has been some snail mortality. I mainly have Grey top shells but there are less than half of them left. I do not know why, part might be predation (which is not all bad as at least they serve as food for other inhabitants). I need to collects some more in any case. The Netted dog whelks are doing well. They are usually hidden below the sand, but as soon as they smell a defrosted shrimp, they come up like a Shai-Hulud. Their plowing through the sand is definitely good in preventing mats of diatoms to appear. Their little cousins the Thicklipped dog whelks are also doing fine. They tend to creep up the Daisy anemone to steal its food. I still have a Sting winkle Ocenebra erinacea which moves slowly but is very pretty. There are a variety of other species such as Blacklined- and Rough periwinkles. The best species however are the truly sublittoral large Turban top shells Gibbula magus (some of which have died as well, one of the shells has been taken over by a hermit crab, wich are also doing fine):


aquarium update 2

The large mop of Harpoon weed has been added to the tank (tied to a large pebble). I also added Grey topshells Gibbula cineraria, several hermit crabs, two Sting winkles Ocenebra erinacea and five shrimp. Although being potentially dangerous to fish, I could not resist putting in a green snakelocks anemone and it looks stunning under the blueish light . It is quite hard to take good pictures as the blue comes out too strong (using a camera and adjusting the white balance does not really work either, as the photos turn too reddish).IMG_1100The Corkwing wrasse is doing fine but is a bit too obsessed swimming up and down one end of the tank (as in this picture). The Purple top shells Calliostoma zyzyphinum are doing well, as they have laid long strings of eggs several times already. (They are a bit weird though; sometimes they lett go of the glass and just lie still down on the sand for one or two days.) The Tunze pump is switched off, as the Harpoon weed catches too much of the current.  I’ve had to remove some seaweeds as there is a brown algae that is slowly but surely covering them (remarkably it does not grow at all on the glass). I will do some water changes, but I do not expect this to help too much, and it definitely is not a permanent solution. I need to dunk a bag of Rowaphos (and activated carbon) in the filter compartment, I had forgotten about that actually….I am also thinking of trying out the ‘wodka’ method, more about that later…

scummy pools

For the first time in a while I had time to nip over to Castle Beach to do a little rock pooling. The tide wasn’t the best and the pools did not look to great either actually; this seemed to be due to a mix of some seaweed species dying off, and some not so great-looking species ones blooming: IMG_0317Lots of Wireweed, Ulva and very fine weeds (the latter are often very pretty under magnified and in water, but not so much as a blob on the rocks). What might be Desmarestia viridis (but don’t take my word for it): IMG_0319Still, there was plenty to see: Orange-clubbed sea slugs for instance and one very weird-looking creature I had never noticed before was clinging on in little groups on red seaweeds under overhangs, the annual sponge Sycon ciliatum:

IMG_0218The Breadcrumb sponge Halicondria panicea can be very nicely coloured: IMG_0240There were a lot of tunicates about. Colony-forming Morchellium argum for instance and this beauty, probably Ascidia mentula (determined by helpful folks at the ‘NE Atlantic Tunicata‘ facebook group): IMG_0276IMG_0279One colony-forming tunicate looked superficially like Botryllus but was much bigger and less pretty, it might be Aplidium nordmanni:IMG_0248 Quite a lot of Sting winkles Ocenebra erinacea were around as well:IMG_0288Finally, I spotted the orange/yellow egg masses of the Cornish sucker (or Shore clingfish) Lepadogaster lepadogaster (see here for an older post on them). However, I also found some that were greyish and had a speckled band, as well as a red dot between the eyes. Local expert David Fenwick told me these are from the Small-headed clingfish Apletodon dentatus, a species I have not yet seen the adults of (see his site for pictures): IMG_0314



Bretagne: Erquy

Last week we crossed the channel to attend a friend’s wedding in Bretagne (Brittany). This of course also called for some rock pooling action, first at the village of Erquy. It was interesting to compare the shores of Bretagne to Cornwall (or at least Falmouth and this small stretch of coast in northern Bretagne). Immediately noticeable was the large amount of oysters on the rocks (with some locals busy collecting them, quelle surprise); these are pretty much absent in Falmouth:


Similar to the Cornish coast, wireweed Sargassum muticum was abundant. This Pacific invader surely must have a large effect on the native flora and fauna:


Invertebrate diversity was strikingly low compared to my local rock pools. For example,  the only fish to be found were Shannies (and not a lot of them), there were no Cushion stars and no large crustaceans except for the shore crab. However, we did find a Common spider crab Maja squinado:

IMG_4495As there was not that much to see, I turned my attention to some of the less spectacular life forms, such as Pink paint weeds, red algae forming a calcified crust. The particular species pictured below forms a patchwork of individuals, crinkling up at the edges where they meet. This could be Litophyllum incrustans, but species are hard to identify by non-specialists such as myself. The little spots on the surface are the openings of reproductive structures called conceptacles.


IMG_4486The European sting winkle Ocenebra erinacea was quite abundant and distinctive vase-shaped egg cases could also be found:



quick rockpooling session

Went to Castle Beach in Falmouth after work this week for a bit of rock pooling. I saw a beautiful grey-red Sea scorpion Taurulus bubalis; I could not tell the difference) or but it was gone before I could even attempt to catch it. Below the much easier to spot Shanny Lipophrys pholis Giant goby Gobius cobitis (after lifting up a rock):


I spotted a small Eel Anguilla anguilla for the first time on the beach; it was quick but I could scoop it up from a very shallow sandy pool. Nice, but not of interest for the aquarium!



Also spotted for the first time: a European sting winkle Ocenebra erinacea. This I took home for the aquarium:


A tiny white Edible crab Cancer pagurus. I do not know if it is an albino or whether juveniles are generally white. I had a bigger one in the aquarium (carapace width 6 cm or so), but every night the light went out it came out of its burrow and started to rearranging the tank, knocking big rocks against the glass. This one is only one cm so I hope it will be better behaved: