A Salt Water Aquarium by A. W. Roberts
Hundreds of young people are now spending their vacation on or near the
sea-shore, and have a good opportunity to study the wonderful habits of
animal and vegetable marine life. Therefore I have undertaken to throw
out a few plain hints as to the management of a salt-water aquarium, in
which these interesting forms of nature can be observed to greater
We will start off with one of the small tin frame tanks sold in New York
so cheap, or a candy jar, or a small-sized wash-tub—any vessel that
will hold water, and is not of iron, tin, or copper, either of which
will poison the water.
After washing out the tank carefully, and filling it with clear
sea-water, we will place in it twelve silver-shrimps (bait shrimps). At
the end of two days they are dead, and you ask why did they die when
they had so much water to live in. They died of suffocation, after they
had breathed all the air contained in the water. We will take out the
dead shrimps, and in the same water place a good handful of ulva
(sea-lettuce, sea-salad), one of the most common of all marine plants,
and place the aquarium in a strong and direct sunlight, by this means
exciting the ulva to work, or, as it is termed, aerify the water. In
less than an hour's time a froth will be seen forming on the surface of
the water, and adhering to the sides of the aquarium. Now observe the
ulva closely, and from its edges and surface very fine threads of
silvery bubbles are pouring out and ascending to the surface. In an
hour's time the water will be thoroughly charged with air. We will again
place twelve more shrimps in the aquarium. This time they will live, and
we will have established a true aquarium—an aquarium based on the
self-sustaining principles of nature, wherein it will not be necessary
to change the water.
Fish as well as human beings breathe air. Air is contained in all water.
After the shrimps had breathed or used the air contained in the water
several times over, it became unfit to sustain animal life any longer,
and so they smothered: just the same as if a number of people were
placed in a room, and all the doors and windows and ventilators were
sealed up tight, so that no new air could enter. They, too, would
suffocate in a short time and die. All plants living in water are
constantly manufacturing new and pure air for their friends and
companions the fishes, particularly when under the action of sunlight.
The great secret in establishing a self-supporting aquarium is to
establish a natural balance of water, fish, plants, and light, so that
none of these agents are wanting in quantity. For instance, a strong
light is required to cause a healthy development of the plant life, but
not direct sunlight, or the plants will be forced too rapidly, and death
will soon follow. Again, direct sunlight will increase the temperature
of the water to such an extent that many of the fish will die. If the
animal life is in excess of the plant life and the water contained in
the aquarium, the animals will perish for want of sufficient air. Again,
if the aquarium is overstocked with plants, so that they are crowded so
closely that the light fails to reach some of them, decomposition will
take place, and everything will become a decaying mass. In fact, it is
only by beginning on a very modest scale, with a very few and small fish
at first, and by gradually increasing the number, that a beginner can
expect to succeed. Over-stocking with animal life and overfeeding are
the two greatest temptations that beset the path to success for the
aquariumist; but patience, perseverance, and critical observation will
eventually lead to success.
The greatest care must be taken, and all shells, rock-work, sand, and
plants must be washed over several times, so that no injurious
substances may be introduced.
Ulva, or sea-lettuce, is to be found in abundance in all our small bays
and inlets at low tide. For the aquarium, those specimens which are
thick in texture, and of a dark green color, only are fit for
manufacturing air. Never be tempted to make use of the light green and
thin specimens, as they are not sufficiently matured, and will soon
decay if placed in the tank.
Scallops when young have a curious way of changing their location by
means of opening their shells and then closing them with great force,
which sends them off at an angle, and so they go dancing along the
bottom till they reach a spot that suits them. This shell-fish forms a
beautiful addition to an aquarium.
HERMIT-CRAB WITH SHELL.
The silver-shrimp, with figured back (all other varieties must be
avoided), I have always considered as constituting a Board of Health in
an aquarium; for no sooner does the water become unhealthy than these
transparent and grasshopper-like creatures will make desperate attempts
to jump out of the tank. These shrimps, and the little hermit-crab, and
the buccinum (a small black sea-snail) are Nature's house-cleaners. They
are always on the look-out for decaying animal or vegetable matter,
which, if not in too large quantities, they speedily devour.
I have seen these black snails gather on a dead fish from a distance of
half a mile; in less than a day's time nothing was left of the fish but
his bones and scales, and these were picked so clean that they had a
polished look. These snails are provided with ribbon-like tongues, from
which project a great number of minute and beautifully constructed
teeth. By passing these tongues backward and forward rapidly they cut
their food down much as a mowing-machine cuts grass. These snails are
the scavengers of all dead fish and vegetable substances found in our
bays and rivers, and to them we owe a great deal of the purity of our
HERMIT-CRAB OUT OF SHELL.
The little hermit-crab lives alone in an empty shell, which he carries
about with him wherever he goes. His reason for living in a shell is
because the hind part of his body is soft, and not protected with a hard
shell, like the fore part of his body. The end of the soft body of the
hermit-crab is provided with hooks, or claspers, with which he holds on
to the inner chamber of his shell so tightly that it is almost
impossible to get him out except by breaking the shell. Very often these
crabs are to be found with a colony of living polyps growing on their
shells. These polyps are very interesting from the fact of their being
the parents of one of our most beautiful jelly-fishes.
When a hermit-crab grows too large, or so fat that his shell pinches
him, he hunts up a new one. First he pushes his long claws far into it,
just to see that no one is inside, and that it is nice and clean; then
he rolls it over and over, often lifting it so as to judge of its
weight. If it suits, he drags it close to the entrance of his old home,
and in an instant he has whisked into his new house. Hermit-crabs are
great house-hunters, often moving just for the fun of it. They are
always skylarking with one another like monkeys, and, in truth, they are
the monkeys of an aquarium. When the water in an aquarium becomes bad,
they are sure to indicate it by leaving their shells, and trying to
crawl out of the tank. In all respects they are the most valuable and
interesting inhabitants of the aquarium.
Pipe-fish are apt to be delicate; still, if your aquarium is in perfect
health, and the water is teeming with minute animal life, they will get
along nicely. Their favorite food consists of the eggs of all small
crustaceans, such as shrimps, sand-hoppers, and lady-crabs. Mrs.
Pipe-fish does not take care of the children, but Mr. Pipe-fish places
them in a long folding pocket that runs along the under side of his body
(which I have tried to show in the engraving). When he lets them out of
this pocket into the vast ocean world to shift for themselves, they are
only a quarter of an inch long, no thicker than a bristle, and almost
Think of a crab decorating himself with bright-colored sea-weed, so that
he is called the dandy-crab! Still, he is not so vain, after all, as he
covers himself with sea-weed that he may escape the sharp eyes and sharp
teeth of hungry fishes. I once had a dandy-crab whose back I had
scrubbed clean, after which I placed him in an aquarium containing a
plain sand bottom. In this tank I also placed a hungry black-fish, who
soon took a nip at him, securing only one of his legs. This so
frightened the dandy-crab that he began searching over the aquarium for
material to cover himself with. In the tank I placed several sea-flowers
(anemones), cut into small pieces. These he immediately seized, and soon
had them fastened over his back, using both claws, he being both right
and left handed, and sticking them on with a kind of glue that he took
from his mouth. In a few days the pieces of sea-flowers began to develop
into perfect flowers, causing the crab to look very gorgeous.
When a crab loses a claw, he does not mind it; in fact, he rather likes
it, as it provides him with an extra meal. All he does is to sit right
down and bite it off to the next perfect joint, eating the fragments of
flesh with much relish. In a week's time a new claw begins to grow. When
a spider-crab grows too large for his clothes, he rips them at the back,
and out he slides, a helpless soft mass. He is now a "soft crab," and
for thirty-six hours he has to hide away, as all fish are hunting for
soft-crab dinners. At the end of thirty-six hours he is hard again, and
has increased one-third in size.
Of all laughable fish a baby swell-fish is the funniest. Beautiful in
color, odd in shape, with the power of blowing himself up into a round
ball covered on the under side with spines, does he not look wise and
important? And he has only two teeth, but can't he bite? Why he swells
himself up so is not exactly known; but I imagine that when he finds
himself inside of a fish, he makes it so uncomfortable for that fish's
general health that the fish is glad to get rid of him.
Next to a young swell-fish comes a young sea-robin, a very interesting
fish. He can make a musical grunting noise when he feels good, and will
spread his beautiful wings, and sail through the water as proud as a
peacock. When he is tired, he likes to bury himself up to his eyes in
sand, for which he uses his two curious hooked fingers. He also uses
these to dig out the sand-shrimps. Some years ago great numbers of very
large sea-robins visited our coast, and were sold in the New York
markets under the name of Dolly Vardens, on account of their possessing
such bright and showy colors.
The shell-fish known as the oyster drill is one of the greatest of all
enemies to young oysters, which he destroys by boring minute holes
through their shells, and when the oyster opens, after death, eating him
up. It is not known how he drills this very minute hole so quickly.
The clinker (serpula) is really a vast marine tenement-house for a
social community of beautiful sea-worms, who build up houses of shelly
tubes twisted and fastened together. Each worm has a stopper, or cork,
to his shell, with which he can close up the entrance to his house.
When this sea-worm is feeding he throws out from the entrance of his
tube a beautiful double plume. These worms are the favorite food of the
sea-horse, who sucks them out with a sharp snapping noise.
The sea-horse is considered to be one of the greatest prizes that can be
obtained for an aquarium. For dignity of carriage, grace of motion, and
beauty of form, he excels all other fish. The papa sea-horse takes care
of his children the same as the pipe-fish, to which he is closely
related; only his pocket is in front of him, and is much larger, and
different in shape. This pocket is lined inside with a fatty substance,
on which the young sea-horses feed till they are strong enough to be
crowded into the world. The sea-horse, when he thinks it time to turn
out his children, presses his big pocket (for he has no hands nor claws)
against a shell or piece of stone, and out swim the young horses. At
first they are apt to form into bundles by locking their tails together,
but as they become accustomed to their new surroundings, and are
stronger, they separate. The male sea-horse displays much pride over his
young, and remains with them several days. Sea-horses can look two ways
at once, as each eye moves independently of the other.
TUBE-FLOWER AND SERPULA.
The tube-flower is very common along our coast. It lives in a long,
thin, light-colored tube, composed of a material resembling horn. It has
the power of stinging slightly, but, for all that, is so beautiful that
no aquarium should be without it. This animal casts off its flower, or
head, every few days, after which a new one makes its appearance.
Sea-flowers (anemones) are always to be found in the same locations with
tube-flowers. Just to think of taking an animal that moves and eats and
breathes, and cutting him up, and that each piece will become a perfect
animal again! Yet such is the case with sea-flowers. When they wish to
produce young, they tear off pieces from their bodies (the base parts),
which soon develop into young sea-flowers. In the illustration I have
shown three kinds of sea-flowers, all of which are common on our coast.
The inside part of a sea-flower is divided by many partitions, forming a
circle of store-rooms; into these rooms he passes his food, where it
remains till all the juices are extracted, after which he passes it out
again the same way it entered. The colors and forms of all our
sea-flowers are wonderfully beautiful. Their thousands of hands (the
fringe-like part), which are constantly moving in all directions in
search of food, remind one of an animated aster.
Small groups of acorn-barnacles, when attached to stones or wood, are
very desirable objects for the aquarium. For a few hours after being
placed in their new home they will remain closed, but as soon as they
become accustomed to their surroundings, one after another will
cautiously throw out his feathery casting-net in search of food. Then
the reaching and grasping become so rapid and general that the eye can
hardly follow their motions.
I feed my fish three times a week with soft or hard shell clams cut
fine, taking great care that no food remains uneaten to taint the water.
For bottoms for aquariums I use coarse bird-gravel, or pebbles
thoroughly washed, with small masses of rock-work.