Glimpses of Ocean Life 38
I do not know a prettier sight than that exhibited by a healthy
aquarium on a fine summer's day; the effect of the sunshine upon it
being to cause innumerable bubbles of oxygen--that look like balls of
quicksilver--to form on every weed, shell, and smallest pebble. On
looking through the transparent sides of the vessel, small particles
hitherto resting on its base, may be seen slowly arising to the
surface of the water, each buoyed up by a miniature gas balloon. The
broad, ribbon like fronds of the ulva, from the self-same cause, float
upwards, and reflect a beauteous emerald hue upon all objects that lie
beneath; while the glass bulb, placed in the tank as before stated, to
denote the density of the water, at such a time belies its mission,
and covered with numerous argent globules, mounts gracefully in
companionship with the sea-weed, until shades of evening approach, when
its buoyancy gradually subsides, and once more it falls to its original
resting-place.
Wherever the above phenomenon is apparent, rest assured that the
aquarium is in good condition. It is, in fact, to the oxygen thus given
out by the plants and infant vegetation that the animals owe their
existence. If no algæ were introduced, the water would become impure,
and unless changed often, your little colony would surely die,--at
least those of its members who were unable to rise above the fluid, and
occasionally breathe the fresh air.
The secret herein involved, that animal and vegetable respirations
counterbalance each other, has only of late years been discovered; yet
it is apparent to any observing eye at the sea-shore; there we never
meet with a rock-pool containing living animals, that is not more or
less adorned with sea-weeds.
The green Lettuce Ulva, so abundant in rock-pools, the sea-grass, which
covers almost every fixed object at the sea-shore, or the well-known
dulse or Chondrus Crispus, form the only sea-weeds that it is necessary
to introduce into an aquarium. In fact, one or two fronds of the Ulva
Latissima alone, will answer perfectly well to purify the water of even
a comparatively large tank. I have often been surprised to find how
small a quantity of algæ was required for the purpose mentioned. After
allowing a single frond to float for a few days in a tank, in which
some sea-water was newly deposited, I took it out, and for an entire
twelvemonth the water remained healthy and as clear as crystal.
The arrangement of the 'stock' of an aquarium is quite a matter of
taste; perhaps no two persons adopt precisely the same plan. It may,
therefore, be advisable, as this matter is so arbitrary, for the writer
to state how his own tanks are mapped out, leaving it to his readers
to imitate the arrangements, or adopt a style of their own as they may
think proper.
At one time I used to make a grounding of sand, but this plan is not
to be recommended, even though it be one highly approved of by several
species of crabs, &c. White pebbles do very well, but I now prefer to
cover the base of the tank with crushed shells, washed very clean.
The following is a sketch of one of my tanks as it at present stands:--
In the centre of the vessel is a _semi-circular arch_, formed of pure
white Sicilian marble, which has to my eye a most pleasing appearance.
Around it, and indeed over the entire floor of the tank, are strewn
chippings of the same material as the centre piece itself.[21] From
the arch, at certain intervals, hang various sized specimens of the
_Mytilus edulis_, which have gradually advanced to their more or less
elevated positions entirely by their own unaided exertions. Near hand
a hardy _A. mesembryanthemum_ has taken up his abode, and sits with
ever expanded tentacles, motionless and happy. On either side of
the Anemone is deposited a riband of Doris spawn, that undulates to
and fro whenever by any chance the water is in the slightest degree
disturbed. Several soldier crabs, of course, act as sentinels of the
tank, and appear to be ever 'on duty,' marching about in all parts
of their subaqueous habitation; while beneath the marble fragments
repose, each with his 'weather eye' open, a small _Maia squinado_, two
long-armed crabs, and a small _Carcinus mænas_. On the sides of the
vase rest a Limpet, a Trochus, and two fine Periwinkles, with skin
of glossy blackness. The shells of either 'Buckie' is covered with
myriads of quicksilver globules, that rest on the tips of the young
and rising vegetation like dew upon the bladed grass. As I write,
upon the inner surface of the water, like a fly upon the ceiling of
a room, an Eolis and two pearly white Dorides lie idly floating in
close companionship. Beneath them, upon the verge of the aperture of a
large empty whelk shell, sits a pretty, cream-coloured Plumose Anemone
(_A. dianthus_). On two blocks of stone repose several specimens of
that mysterious animal the Pholas, who, by my unkindness, are thus
made to become members of the marine 'houseless poor.' Several young
specimens of these bivalves are seated, in a piece of rock, and daily
engaged in 'boring.' A stick of wood, formerly the slender twig of
a tree, is thickly clustered with fairy-handed acorn barnacles and
serpulæ, and being placed against the glass, the movements of these
singularly beautiful creatures can be watched with ease. Then there are
two Star-fishes, a pack of three little Blennies, and a Five-bearded
Rockling, whose singular movements I have previously alluded to.
Against the arch some fronds of ulva are anchored, while at chosen
spots specimens of delicate sea-weeds are also fixed--these rising up,
and being magnified through the sides of the vase, have a pleasing
effect, even to the eye of a child.
[21] The arch was cut from one of the waste pieces, of which there are
always a large number, lying in a marble mason's yard, and cost but a
few pence. The 'chippings' may be had in most cases for the trouble of
carrying them away.
It is a pretty sight to watch the fishes glide under and around the
marble arch, or throw themselves upon its highest point, there to enjoy
the fresh air, and have a pleasant 'crack' together. This __EXPRESSION__ is
literally correct, for the Blennies, when thus situated, usually make a
kind of noise not inaptly expressed by snapping the nail of the thumb
and finger together.
The foregoing animals which constitute the entire stock of one tank,
are, I am proud to state, all in a healthy condition, and if we may
judge by appearances, all contented and happy. It will be from no fault
of mine if they do not long continue thus, and exhibit no signs of
yearning for their native haunts by the sea-shore.
'Those gay watery grots--
Small excavations on a rocky shore,
That seem like fairy baths or mimic wells,
Richly embossed with choicest weed and shells,
As if her trinkets nature chose to hide
Where nought invaded but the flowing tide.'
In another tank I have introduced as a centre object a fine piece of
white coral, the higher branches of which rise above the surface of the
water. The roughness of the coral seems to be much approved of by many
of the animals, who are not slow to avail themselves of the facility
thus afforded them of climbing and otherwise exercising their peculiar
propensities. When purchasing coral, care must be taken to procure a
specimen that has not undergone any cleaning process, for although such
may be more pleasing to the eye, it is not so suitable for a 'centre
piece' as the cream-coloured, and less expensive coral.
A third aquarium which I possess is fitted up in a somewhat novel
style, which offers, for certain purposes, some slight advantages over
others that I have seen employed. It can be adopted in almost any kind
of tank; but the one under consideration is circular in form, and is,
in fact, a bell-shaped inverted fern glass, the knob of which is sunk
into a stand of wood supported on three legs.
The plan alluded to, which was suggested to the writer by an ingenious
friend,[22] consists of the introduction of a floating centre piece
composed of gutta percha, which serves as a resting place for various
small animals, such as Actiniæ, Mussels, Barnacles, Serpulæ, and
even Pholades and Cockles. At the base of the vessel, which is quite
uncovered, rest sundry members of the crustaceous family, whilst
fishes of various kinds swim freely about over the entire vessel free
from all annoyance.
[22] Mr. Walter Hardie of Edinburgh, who has been my companion in many
a delightful excursion among the rock-pools of the shores of the Frith
of Forth, and to whom I feel myself greatly indebted for much valuable
information relative to the subject of marine zoology.
The question will doubtless be asked, 'How can I procure the centre
piece here spoken of?' I answer, Make it yourself; a little skill
combined with patience and gutta percha being all that is required. The
following directions will serve to aid the young reader who may wish to
test his manipulative powers.
Procure a thin piece of gutta percha, and lay it in hot water for a few
minutes until it is thoroughly soft and pliable. Then get a globe--an
orange will do if nothing better offers--and cover it with the above
material. Having done this, throw it into cold water, and when hard,
cut the fruit in two, so as to leave the gutta percha cast to the shape
of each half.
Next make a circular tray about eight or nine inches in diameter, and
turn up its edge about half an inch all round. Then heat the brim of
each cup, and fasten them to the centre of the upper and under part of
the 'tray.' The structure will then float in water. This, however, is
not all that you want, as your centre piece must always be entirely
immersed. First bore a few holes in the tray, then fix a pretty shell,
with a hole in it, to the base of the lower 'cup,' and also form a loop
of gutta percha, from which to suspend, by means of a piece of silk, a
fragment of stone or marble of sufficient bulk to balance the centre
piece, and sink it an inch or two below the surface of the water.
At the centre of the upper cup fasten a small piece of gutta percha
tube, at the end of which the valve of a Pecten may be attached as an
ornament. The whole structure must be gently warmed and entirely coated
with fine sand; then tastefully decorated with shells and fronds of
green Ulva, and the crimson Delesseria Sanguinea.
Sometimes I introduce a globe of glass as a buoy, and to its centre attach the tray of gutta percha.
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