top ten animals for the unchilled aquarium: 10 – 6

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

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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

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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

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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.

Mud pooling

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

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

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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