IN THE AQUARIUM
by Ron Barrett
The Tompot Blenny, Parablenniusgattorugine or Gattorugine is a small fish (rarely more than 15 cm in length) inhabiting the inshore waters of northwest Europe. It ranges from the British Isles south to the Mediterranean and possibly a little beyond.
Description & Habits
On the lower shore its appearance is sporadic, usually as only one or two isolated specimens. It is likely to be more common in the shallow sublittoral, although again as isolated specimens. It feeds mainly on hydroids, small gastropods, amphipods, decapod crustaceans, brittle stars and, most unusually, sea anemones. This latter habit can often turns the fish into an aquarist's nightmare.
Let us examine the reasons why Parablennius gattorugine
makes such a difficult aquarium subject. Firstly, the Tompot's alternative
name Gattorugine. This actually translates from the Italian (Latin)
as "Rusty Cat (or Dog?). Examine your pet Tompot
head-on and you will see why! The "rusty" description refers
to the brown "rust" patch marking on the fish's body.
Now the point to make is that your 'rusty cat's' jaws can pose as a row of close-packed minute teeth purpose-built for barnacle crunching, crab chopping and sea anemone slicing. It is these teeth, plus the heavy muscular body of the Tompot, that enable it to wreak such havoc in an aquarium. And it can also develop a liking for aquarist's fingers!
In a mixed Tompot/invertebrate aquarium, one finds that, invariably, the sea anemones are the first victims. Of these, my studies have shown that Sagartia troglodytes is a firm favourite. Dahlia Anemones, Urticina spp., come a close second once the protective gravel covering has been torn off. Then any small sea anemones that are left. Only one species regularly escapes the Tompot's jaws, Calliactis parasitica. It is just too tough!
At one time I held the opinion that a Tompot would not attack a Snakelocks Anemone, Anemonia viridis. Wrong! The Tompot is a canny hunter. Mine waited until the Snakelockshad reproduced (split in half), chose its moment and then launched itself at the area where the anemone was most vulnerable, the split point.
The strange thing was that one got the impression from the fish's reactions that it could well have been eating hot coals. Nonetheless, the Snakelocks was duly devoured.
An attack on an anemone is fascinating to watch. The Tompot edges close to its target, using its large pectoral fins. Cocks its head to one side, as if taking aim, checks to make sure there is no aquarist close by with an aquarium net, and launches itself violently at the unfortunate victim. Then a twist and a tear and the poor anemone is on its way to oblivion.
Large anemones are consumed over a period of days, the Tompot nearly always working on one victim at a time. It is by no means clear whether your average sea anemone constitutes much in the way of nutritional value. However, I have been informed that the French used to prepare a dish of fried Snakelocks Anemones. I'd much prefer fresh stinging nettles any day!
As the days lengthen and the warmer weather arrives, the lady Tompot's thoughts turn to breeding. Usually, in April and May eggs are laid, either under stones or in crevices where they are fertilized and guarded zealously by the male fish. The fortunate aquarist may have the pleasure of witnessing the event in his/her aquarium.
Unfortunately, it is at about this time that the great "I'm taking all my bloody Tompots back" game begins. Yes, mention the word breeding to your 'Rusty Cat' and what does it do, why, it becomes five times more aggressive and, even worse, extremely territorial. Now we have hermit crabs with no eyes, pipefish with no dorsal fins (and occasionally an inch [25 mm] or so shorter than when they were caught), and the remains of prawns and shrimps who strayed too close to the 'beast's lair' floating in and polluting the water. On top of all this, every other fish that your Tompot cannot catch/eat is being chased around the aquarium until it is exhausted. Where then does all this leave the beleaguered aquarists? Probably in need of a handy list of tips.
Tompot Blenny Database
Wet Thumb (Marine Aquaria)
1) Keep stocking levels low.
I suggest a couple of 8 cm fish only in a 4 ft. tank.
2) Keep Tompots separate from invertebrates.
Only the largest crabs will survive.
They will still be vulnerable when moulting.
3) Keep the Tompots well fed.
Boiled mussel is a staple.
Increase the food as the temperature
4) Be careful with the other fish kept in the same aquarium.
The Shanny, Lipophrys pholis can sometimes be kept in the same tank for short
5) Include barnacle covered rocks in the aquarium to keep the
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Tompots introduced into a tank full of Blennies, Lipophrys pholis, found themselves unable to compete for food in the long term. The ordinary Blennies were quicker on the uptake for boiled mussel, and crabs. If fed on live prawns, Tompots are more adept.
The sea anemone Calliactis parasitica, (pic) a commensal with hermit crabs, does not survive in the long term with Tompot Blennies. The fish worry the anemone so much that it is unable to open its tentacles to feed.
The Tompot Blenny could possibly be confused with the rarer Montagu's Blenny, Coryphoblennius galerita.
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Every marine creature is of interest and this includes marine mammals, sea birds, shore birds, vegetation above the high tide level but still influenced by the sea, strandline animals, estuarine fish and invertebrates, as well as fully marine fauna like Basking Sharks. All sightings of this massive plankton feeder are certainly worth sending in.
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