Category Archives: anemones

aquarium update: snails

Posted on by under algae, anemones, aquarium update, crustaceans, molluscs

Time for an update. The five Snakelocks anemones have settled and are doing very well (I have fed them some defrosted shrimps which they quickly devour). The Leach’s spider crab was sitting happily under one of the anemones until it decided to move behind a piece of slate and now does not show itself much anymore. Perhaps this has to do with a prawn I introduced, although I have not seen any scuffles. I have to see what I’ll do about this. If it is really shy then I perhaps have to choose between keeping it or introducing fish. In any case I have seen it munching on some algae and a dead Cushion star and it seems to do OK.

IMG_6422

The main problem I have is the dreaded return of algae…There is quite a diversity of them: fuzzy green ones, darker green blotches, slimy purple ones, brown diatoms and more. All interesting organisms surely but I do not want them to take over the tank! I have used food sparingly and used the skimmer most nights, but now have also removed my daylight lamp, to leave a single actinic lamp (see this post about lighting). I still have to get used to this new look, but less light must surely help. Most interestingly, I have enlisted the help of 80 or so grazing snails. Mainly the Common periwinkle Littorina littorea and the Flat top shell Gibbula umbilicalis but also some other species, including two very small Painted top shells Calliostoma zizyphimum. I never had many snails in my aquarium, as they were always eaten by Shannies, but hopefully they will survive this time. I will dunk in a lot more snails, and keep an eye out which species does best. A Flat top shell (picture taken using my olloclip macrolens for the iPhone):

IMG_6468

One returning encrusting red algae is actually a seaweed, with new ‘leaves’ growing from the round crusts. I suspect it is Devil’s tongue weed Grateloupia turuturu. I have been scraping it off the glass, except from the corners where the scraper is of no use, but will let the rest sit and see how it grows:

IMG_6431

I also noticed that Sea lettuce Ulva has started to grow from the slate. The aquarium does not look that nice yet, but with the new animals there is plenty to watch in any case!

new inhabitants

Posted on by under anemones, aquarium update, crustaceans, Red Sea Max 130D

Last weekend I went for a bit of snorkeling off Pendennis Point to catch some new inhabitants of my tank: some Snakelocks anemones and a Leach’s spider crab (just one for a start). Although it was overcast and late, it was nice to be in the water. I was lucky to straight away find a diving knife, this helped me to cut of some kelp housing snakelocks. I took a perforated plastic Lidl bag with me in the water to serve as a net for the crab, low tech but it worked fine. The tricky thing was to get the snakelocks from the kelp afterwards (I did not want a load of rotting kelp pieces in the tank):

IMG_6148

With some finicking I could get the anemones off the kelp and on the rocks or gravel. The Leach’s spider crab (decorated with small pieces of red seaweed) quickly hid behind a rock. However, after two days it was accustomed to its new surroundings and found a place underneath one of the anemones right in the front of the tank:

IMG_6216

animals that did not do that well in my aquarium…

Posted on by under anemones, cnidarians, crustaceans, echinoderms, fish, molluscs, not suitable for the aquarium, Red Sea Max 130D, tunicates

A while back I wrote two posts on my personal top ten animals for the (unchilled) aquarium (here and here). Of course, there were also organisms that were not such a success. Animals can be unsuited for the aquarium for many reasons, and of course this depends on the size of aquarium, the combination of animals and what you define by ‘unsuited’; so please keep in mind that the following is a personal account!

Aggressive species: Another reasons that makes animals unsuitable for a community tank is that they are bullish. (Animals becoming too big is not a real problem for the native aquarium as you can release them again and replace with smaller individuals.) Crabs often get rowdy for instance. I kept a small (5 cm carapace width) Edible crab Cancer pagurus for a little while (his name was Barry). It would bury (Barry!) itself during the day, but as soon as the lights turned off it would go about and rearrange the tank. Rocks weighing over a kilo were knocked against the glass and I found a Cushion star cut in two. It was quite an operation to remove it from the tank using a net (but during all that rummaging I interestingly saw bioluminescence in the tank which was very cool). Shannies like to feed on snails and hermit crabs and so in a relatively small aquarium at least, so sometimes you have to choose between one or the other:

IMG_2240

Truly littoral species: I had a couple of limpets Patella vulgata in the aquarium that just sat in the same place on the glass for months. At this time, algal growth was a problem, so I should have known if they had moved during the day or night by the tracks they would have made but they did not move a millimeter. The animals seemed a bit thinner in their shell, but seemingly they can survive for very long periods without food. Not being able to emerge from the water as they do normally seems to be a big problem for these animals.

Secretive species: Other animals simply are too shy or live underneath rocks; no point really in putting them in the aquarium if you cannot see them. This happened with Broad-clawed porcelain crabs, a Shore rockling and also a Shore clingfish (although hidden, all of these animals did survive for a long time). I have seen Brittle stars in a Mediterranean aquarium but the ones found in the intertidal here tend to live under rocks and I never saw one back in the aquarium. A Sand star Astropecten irregularis quickly buried itself in the gravel:

IMG_5177

Filter feeders: I quickly realized that filter feeders, mussels or tunicates for example, were very difficult. There simply were not enough algae growing in the water to feed them (unfortunately, at times there were plenty of algae growing on the rocks and on the glass). One way to keep filter feeders is to separately cultivate algae for food. A really nice blog describing such a project can be found here. Another solution might be to feed these animals with artificial plankton, which is available commercially. This requires very good skimming to get rid of excess nutrients though. Both options I find too cumbersome at the moment. Having said all this, one filter feeder managed to survive for many months in my aquarium: the variegated scallop.

Other fussy eaters: Worm pipefish did OK in the aquarium, but that was probably because I regularly brought in new seaweeds housing fresh zooplankton. Unlike Mullet, Gobies or Blennies, I have never seen them take frozen food and therefore I will not keep them again until I can provide them regularly with live brineshrimp or similar. Snakelocks anemones always did well in the aquarium, but Beadlet and Strawberry anemones didn’t (they actually did not die but seem to shrink rather than grow over time). The former are able to grow because of their symbiosis with photosynthesizing algae and so do not rely as much on food. I must say that the latter two  species are probably relatively easy to keep when you make the effort to regularly dunk a piece of dead prawn on them. The European cowrie Trivia monacha feeds on tunicates which I had trouble keeping alive and so they are unfortunately not an option yet:

IMG_0987

Unknown reasons: On a few occasions a species just died and I had no idea why. The only thing this taught me was to not try that species again. This happened to a Common starfish Asterias rubens:

IMG_2835

snorkeling at pendennis point

Posted on by under anemones, crustaceans, seaweeds, snorkeling

The sun was shining this weekend and the sea water is currently at its warmest so we went out for a bit of snorkeling off Pendennis Point in Falmouth. My experience with the iPhone waterproof case was not that good, so I took my Panasonic Lumix (DMC-FT10) along (which is not too great either!). The seaweeds are dying off mostly; the kelp is covered by bryozoans and hydroids to the point that they are completely fuzzy:

P1030862

I mentioned in the previous post that the Spiny starfish Marthasterias glacialis was common in rock pools; bigger ones can be found when snorkeling:

P1030845

Big Snakelocks anemones Anemonia viridis were everywhere and perhaps half of them had a little Leach’s spider crab Inachus phalangium associated with them. Wikipedia tells me that these crabs eat the anemones’ leftover food and also their mucus:

P1030869

This hour of snorkeling gave me some inspiration for a new aquarium set-up: less seaweeds (specifically less dying seaweeds clogging up the filter and releasing nutrients) and more rocks. On top of these a couple of big snakelocks with spider crabs and some Two-spotted gobies Gobiusculus flavescens. The latter are very common and pretty. I will have to catch them underwater with a net though, which will probably be difficult…

top ten animals for the unchilled aquarium: 5 – 1

Posted on by under anemones, crustaceans, echinoderms, planted aquarium

OK, part two of my list of fun and easy species to keep in an unchilled native marine aquarium (see here for numbers 10-6). I will later post about species to avoid, and of course also about easy seaweeds to keep.

5: juvenile crabs

IMG_2331

Crabs are active and interesting to watch, however, in a community tank they should not be too large as they can be quite destructive as well. Juvenile Shore crabs Carcinus maenas are an option, or a variety of crab species that stay small, such as Pirimela denticulata (I am not too sure what species the above pictured crab is, but it is still doing well four months after collecting it).

4: Squat Lobster Galathea squamifera

IMG_0094

Squat lobsters Galathea squamifera can be a bit shy but are entertaining to watch as they scuttle about. Very common under rocks in silty areas.

3: Snakelocks Anemone Anemonia viridis

IMG_0102Very pretty and common anemones that are easy to keep. Beadlet anemones Actinia equina and Strawberry anemones Actinia fragacea survived in my aquarium as well but they seemed to shrink a bit over time rather than grow and these species can retract their tentacles which looks less nice. I did not specifically feed my anemones by dropping artemia or food pellets on them. The photosynthetic capabilities of Snakelocks anemones due to their algal symbionts probably makes it easier for them to thrive when food is relatively scarce. Beware for the tentacles of larger individuals though, as they can sting!

IMG_1333

2: Common prawn Palaemon serratus

IMG_2392

Prawns* have been a rage in tropical freshwater aquariums for years but people forget that there are very pretty ones right in our seas. I must admit I have not got round to checking rostrum (the ‘nose’) structures to differentiate between several closely related Palaemon species, but I think I have the Common prawn. They are always foraging and flock to any new object in the aquarium to check for edible bits. If the pumps are switched off they will swim and compete with the fish for food.

* or shrimp, these two names can mean different things in different English-speaking countries. In other languages ,like my native language Dutch, we only have a single word (garnaal) for these critters

1: Cushion star Asterina gibbosa

IMG_0356My numbers 2, 3 and 4 could have been number 1 as well, but I ended up picking the very common Cushion Star. Although grey and just an inch in size, these quintessential rock pool inhabitants are active, hardy and just plain cool!

top ten animals for the unchilled aquarium: 10 – 6

Posted on by under anemones, crustaceans, echinoderms, fish, molluscs

As the aquarium is currently in a state of limbo, I thought it would be fun to take a look at the critters that have been most rewarding to keep in the year or so I’ve had my aquarium. Based on my personal experience, I have made an, admittedly completely arbitrary, top 10 of animals for a Cornish (or North-Western European) marine aquarium. I picked animals that were both easy to collect (i.e. common), easy to keep (not requiring live food and resistant to water temperatures up to 25C) and fun to watch. Here goes with the first part of the list!

10: Netted dogwhelk Hinia reticulata

IMG_0748

Not the prettiest of molluscs maybe, but very easy to find and very easy to keep. Burrowing in sand, and moving surprisingly fast over the bottom when smelling food. Their smaller (and prettier) cousins the Thicklipped dogwhelk Hinia incrassata never survived for long in my unchilled tank.

9: Common hermit crab Pagurus bernhardus

IMG_1020Hermit crabs are especially fun to watch scurrying about. Mine never really lasted very long but that is probably because of predation by blennies and gobies (see below)….

8: Shanny Lipophrys pholis (or Rock goby Gobius paganellus)

IMG_0203Shannies are probably the most common fish to find in rock pools. They are very easy to keep, their coloration is not particularly vivid but not dull either and they are quite active. The only downside is that they prey on molluscs and other small critters. Feeding them a bit more might prevent this, but especially the rock gobies are so voracious that I doubt that (one was so swollen I thought it was dying, until I realized that it had gorged itself on defrosted artemia…). Montagu’s blenny Coryphoblennius galerita is prettier and smaller than the shanny but much harder to find (see this post for experiences with other fish species).

7. Thicklip grey mullet Chelon labrosus

IMG_0675

Most rock pool inhabitants live on or near the rocks, but it looks nice if the aquarium also have some fish swimming in the water column. Mullet are very common, and small individuals form nice silvery schools (which are almost impossible to photograph as you can see). They don’t really interact with the other tank inhabitants.

6: Painted top shell Calliostoma zizyphinum

IMG_1949

One of my favorite local molluscs: a bright purple shell with an orange colored snail inside. Shells are never covered with algae as the snail wipes it clean with its foot (the shell can still be damaged of course as seen in this individual).

The next post will feature the top 5 of animals for the unchilled aquarium.

Piran aquarium

Posted on by under anemones, echinoderms, fish, iPhone, non-Cornwall, not suitable for the aquarium, public aquarium

I have a love/hate relationship with public aquariums: love because I am a bit aquarium-mad, and hate because quite a lot of them really are disappointing. Of course, I know all too well that it is not easy to create (and maintain) good-looking aquariums. Also, the paying public needs to be pleased and it wants to see ‘nemo’s’ and sharks which often results in the same sets of standard tanks. Although I do understand the need to educate the public, I am quite allergic to all kinds of video installations and boring props taking up space that could have been filled with tanks. I am not even talking about walkways decorated with fake polyurethane caverns or ornamental treasure chests in tanks…

I try to visit public aquariums whenever possible and from now on will review them on this blog, specifically highlighting the smaller, temperate saltwater tanks that could serve as inspiration. Last week I was in Slovenia for work and a short holiday and passed by the lovely town of Piran which has a small (about 10 large and 10 small tanks) public aquarium, all with local animals. Here is one funky looking tank housing some writhing moray eels and Grey triggerfish Balistus capriscus, the latter also present in Cornish seas:

IMG_4321

IMG_4393

I am not so sure about larger-sized Mediterranean Sea aquariums, as there is not a lot of potential to make them visually appealing: some rocks and the odd human implement as decoration and the fish are often not overly spectacular (see the Two-banded bream Diplodus vulgaris below). If I were to go for a large, non-planted rock tank, I would try my hand at an African Great Lake aquarium instead, with the fish being more diverse, more interesting and more beautifully colored.

IMG_4330

 One of the largest fish on display was the Leerfish Lichia Amia. It was a shame to see such a large pelagic fish in a tank with its head completely deformed due to it bumping against the glass:

IMG_4369

I was most interested in the smaller aquariums. These housed some species that can also be found in Cornwall, such as the Tompot blenny Parablennius gattorugine and the fantastic John Dory Zeus faber (which occurs around the globe):

IMG_4349

IMG_4384

Some of the small aquariums were quite sweet. No seaweeds to speak of (although I saw some Ball algae Codium bursa) but lots of nice invertebrates such as sea cucumbers, clams, whelks, sponges, anemones as well as a variety of fish:

IMG_4314

IMG_4360

IMG_4358

Especially amazing was the stony coral Astroides calycularis:

 IMG_4376

A Small rockfish Scorpaena notata:

IMG_4315

All in all an interesting little visit (I had to rush a bit taking pics as the rest of the family is not as keen on ‘the mysteries of the deep’ as I am…). Lots of types of invertebrates that I would like to try to keep such as sea cucumbers, but for the moment I will focus on seaweeds. I had no time to have a proper look at the rocks outside (the Mediterranean has very small tide differences anyway) and I had not even brought my snorkel. From the glances I got, the Adriatic coast did not have much on the Cornish coast though!

new sand

Posted on by under algae, anemones, crustaceans, fish, molluscs, not suitable for the aquarium, planted aquarium, Red Sea Max 130D, seaweeds

Welcome to this most obscure of blogs, my dear reader. The aquarium is a bit of a mess at the moment for a variety of reasons. First of all there are a lot of algae growing; I have a bag with Rowaphos hanging in the back compartment to remove phosphates but this does not seem to help much (I have had good experiences with before though). Second, one of my pumps broke and so filtration runs at half capacity. Third, the mixed success of planting many different seaweeds has left loads of detritus in the tank. I have made large water changes which helped a bit. An additional tank for experimenting would be nice to have… Fourth, I have been unlucky with some of the seaweeds: the Wireweed grew really well, but the large size meant it caught a lot of the current and was easily dislodged. The Dudresnay’s whorled weed Dudresnaya verticullosa was growing really well (see here) but broke off from the rocks and could not be replanted:

IMG_2996

I could not attach the fine red seaweed (see last post) either and did not want to have it floating around so I have removed it. My nice red seaweed streaming from the pump outlet, most probably Devil’s tongue weed Grateloupia turutu (as the name indicates, another invader from the Pacific), broke of. A crap picture of both weeds:

IMG_3128

I changed the white gravel with finer, beige Maerl gravel (Cornwall’s equivalent of coral sand, see previous post) here placed in a bowl for contrast:

IMG_3133

I released my Shanny as well as the largest of the two Rock gobies. The former attacked to many of the snails (it was getting a bit of a mollusc graveyard) and the latter was just too voracious in general. The final straw was seeing it swimming around with half a Worm pipefish sticking out of its mouth (I still have a bunch of those). The Shore rockling did not survive, but I caught a glimpse of the Shore clingfish when I removed some of the rocks from the aquarium. The juvenile albino Edible crab (if that’s what it is) and the European sting winkle Ocenebra erinaceus I recently caught both still do well, as is a juvenile Shore crab Carcinus maenas:

IMG_3147

The Netted dog whelk Hinia reticulata is not one of the most impressive looking snails, but they do very well in the aquarium, burrowing and moving around:

 IMG_2167

I am not sure whether replacing one of the actinic lamps with the daylight lamp was such a great idea, the tank looks too yellowish now, especially with the Maerl sand…However, I will stick with it and see whether it helps future attempts to successfully keep Bushy rainbow wrack Cystoseira tamariscifolia (i.e. to retain it’s iridescence). If not, I’ll go back to the original lighting. I will not do too much with the aquarium in the near future as I want to get rid of the algae first. There are not many critters in the tank, which should help (I have only introduced a nice big Snakelocks anemone Anemonia viridis recently). I will do some more water changes and order a new pump. Only then will I slowly start experimenting with seaweeds again.

I am still unsure about the chiller, but with the weather getting warmer it might be more than just a luxury to have one. Apart from the price, it standing on the floor next to the aquarium with tubes sticking out is what I don’t like about the idea though. It will also not be silent, but perhaps I could get away with disabling the noisy hood fans, resulting in an overall quieter aquarium. The stripped-down tank (note that the red encrusting algae/seaweeds at the top of the tank have died (turned white) as they were exposed for a couple of hours when changing water):

IMG_3139

 

Mud pooling

Posted on by under anemones, crustaceans, eggs, fish, molluscs, rock pooling, sponges

When it was very low tide last week, I decided to skip the ‘rock pools proper’ on my local beach in Flushing and to check out the zone just below where the rocks and the sandy bottom of Penryn River (an arm of the Fall Estuary) meet. All common rock pool inhabitants – winkles, top shells, edible crabs, worm pipefish and shannies – still live here, but some other organisms are more abundant here than in the rock pools.IMG_2881

Sponges are very common in this silty environment, especially the Estuary sponge Hymeniacidon perleve:IMG_2877

The Breadcrumb sponge Halichondria panicea:IMG_2882

In addition to sponges, I noticed quite a lot of the colony-forming ascidian Botrylloides leachi (see previous post). That explains why I could also find a couple of European cowries Trivia monacha, their predator. Also very common here are the Variegated scallop Chlamys varia and the Thicklipped dog whelk Hinia incrassata (top right picture). I am not sure what the slimy beige stuff is!IMG_2920

I spotted a couple of new things as well, the Red speckled anemone Anthopleura ballii:IMG_2901

IMG_2905

Also a first, a Sea spider Nymphon (gracile?):IMG_2886

IMG_2892

I found a large patch of these beautiful eggs:IMG_2931

and someone guarding them, a rock goby Gobius paganellus:IMG_2935

A Butterfish Pholis gunnellus:IMG_2947

Very common were little Squat lobsters Galathea squamifera (no picture), rapidly swimming backwards to escape. Even more abundant were these little Hooded prawns Athanas nitescens:IMG_2924

tank update

Posted on by under anemones, aquarium update, crustaceans, echinoderms, molluscs, planted aquarium, seaweeds

Time for an update on the tank. Switching to two lamps instead of one looks good but has not brought the iridescence of the Bushy rainbow wrack back. I could not resist putting a new specimen in. Iridescence is defined as the property of certain surfaces to appear to change color as the angle of view or the angle of illumination changes. Left: viewed from below, right: viewed from above.

IMG_2407IMG_2409

I noticed that the underside of the rock the weed was attached to harbored a nice little strawberry worm, but before I could photograph it, the large rock goby gulped it down. It is noticeable that the fish have full bellies after putting in a new piece of seaweed, which is no surprise as there is so much growing on and in it.I have seen the very cute amphipod Caprella acanthifera which looks like a tiny, marine cross between a praying mantis and a caterpillar, but since they did not come not near the glass I could not get a good shot. I have seen one Cushion star Asterina Phylactica as well, which looks nicer than the light grey Asterina gibbosa I have. I also noticed a couple of Cerithiopsis tubercularis (3-4 mm):

IMG_2102

The tank is completely full of snakelocks anemones, hundreds maybe:

IMG_2410

IMG_2107

In the foreground an Idiotea isopod; there are many of these sitting on seaweed branches and occasionally swimming around, although most of them will probably be eaten by now. Finally, three seaweeds have started to grow from the pump outlets. Dudresnay’s whorled weed, a fine purple weed and a broadleaved red seaweed. I have placed adult plants of the latter species (30 cm or so)  in my aquarium before, but these were quickly eaten. It is either a type of laver or dulse, but I am not sure. It has also settled on the glass, but seldomly grows ‘leaves’ on there. Growing in the water current protects the weeds from predation from shrimps, let’s see how big they can grow!

IMG_2354