Dear Sir,--When I happen to visit a family where gold and silver fishes
are kept in a glass bowl, I am always pleased with the occurrence,
because it offers me an opportunity of observing the actions and
propensities of those beings with whom we can be little acquainted in
their natural state. Not long since I spent a fortnight at the house of
a friend where there was such a vivary, to which I paid no small
attention, taking every occasion to remark what passed within its narrow
limits. It was here that I first observed the manner in which fishes
die. As soon as the creature sickens, the head sinks lower and lower,
and it stands as it were on its head; till, getting weaker, and losing
all poise, the tail turns over, and at last it floats on the surface of
the water with its belly uppermost. The reason why fishes, when dead,
swim in that manner is very obvious; because, when the body is no longer
balanced by the fins of the belly, the broad muscular back preponderates
by its own gravity, and turns the belly uppermost, as lighter from its
being a cavity, and because it contains the swimming-bladders, which
contribute to render it buoyant. Some that delight in gold and silver
fishes have adopted a notion that they need no aliment. True it is that
they will subsist for a long time without any apparent food but what they
can collect from pure water frequently changed; yet they must draw some
support from animalcula, and other nourishment supplied by the water;
because, though they seem to eat nothing, yet the consequences of eating
often drop from them. That they are best pleased with such _jejune_ diet
may easily be confuted, since if you toss them crumbs they will seize
them with great readiness, not to say greediness; however, bread should
be given sparingly, lest, turning sour, it corrupt the water. They will
also feed on the water-plant called _lemna_ (ducks' meat), and also on
small fry.
When they want to move a little, they gently protrude themselves with
their _pinnae pectorales_; but it is with their strong muscular tails
only that they and all fishes shoot along with such inconceivable
rapidity. It has been said that the eyes of fishes are immovable; but
these apparently turn them forward or backward in their sockets as
occasions require. They take little notice of a lighted candle, though
applied close to their heads, but flounce and seem much frightened by a
sudden stroke of the hand against the support whereon the bowl is hung;
especially when they have been motionless, and are perhaps asleep. As
fishes have no eyelids, it is not easy to discern when they are sleeping
or not, because their eyes are always open.
Nothing can be more amusing than a glass bowl containing such fishes; the
double refractions of the glass and water represent them, when moving, in
a shifting and changeable variety of dimensions, shades, and colours;
while the two mediums, assisted by the concavo-convex shape of the
vessel, magnify and distort them vastly; not to mention that the
introduction of another element and its inhabitants into our parlours
engages the fancy in a very agreeable manner.
Gold and silver fishes, though originally natives of China and Japan, yet
are become so well reconciled to our climate as to thrive and multiply
very fast in our ponds and stews. Linnaeus ranks this species of fish
under the genus of _cyprinus_, or carp, and calls it _cyprinus auratus_.
Some people exhibit this sort of fish in a very fanciful way; for they
cause a glass bowl to be blown with a large hollow space within, that
does not communicate with it. In this cavity they put a bird
occasionally; so that you may see a goldfinch or a linnet hopping as it
were in the midst of the water, and the fishes swimming in a circle round
it. The simple exhibition of the fishes is agreeable and pleasant: but
in so complicated a way becomes whimsical and unnatural, and liable to
the objection due to him.
"Qui variare cupit rem prodigialiter unam."