Marine aquaria: their construction, arrangement, and management, with full information as to the best animals and seaweeds to be kept, how and where to obtain them, and how to keep them in health

Preface

nN every department of study those are procahly best qualified to act as teachers who have actually encountered, and more or less successfully overcome, the difficulties surrounding the particular branch of science or art to which they have applied themselves. It is from this point of view that I venture to address the readers of the following pages, in which I have endeavoured to set forth the principles and practical construction of the Marine Aquarium in a scientific, as well as a popular, manner. If those who are learned in the technical phrases of the naturalist’s work-room do not find therein so large a space allotted to scientific details as they would desire, I will ask them to remember that the book is principally intended for those who, while seeking rest and recreation by the seaside, are apt to find the time hang rather heavy on their hands, in the hope that it may supply them with a means of employing themselves in a pursuit which is eminently healthy in itself, and may afterwards lead to a desire for a more extensive knowledge, which can be studied in the larger and more scientifically-written manuals.

The nomenclature I have most extensively followed is that of Mr. P. H. Gosse, bringing it more up to date in the case of Sea- Anemones by reference to Pennington’s ‘‘British

VI

PREFACE.

Zoophytes,” and occasionally, in the case of fishes, to YarrelFs “ British Fishes.”

In the space covered by so small a book, comparatively speaking, as this is, it is of course impossible to give accounts of numerous species of the marine animals, fishes, and plants, which inhabit our shores. I have therefore chosen for notice those which are especially representative of their various families, and which have been practically kept in an aquarium by myself or others, and have therefore proved themselves suitable for domestication.

Contents

CHAPTER PAGE

II. The Tank, and its Construction ... ... 8

III. Fitting up the Tank ... ... ... 17

CHAPTER I. IN trodiJctioN

LTHOUGH the study of marine zoology has made enormous strides in the last few years, there are still many people who take their annual holiday at the seaside without the least idea that there is a fund of amusement and reflection close to their hands, which can he easily enjoyed both while there, and afterwards in the inland country, or even in the heart of London itself.

In these chapters it is intended to give a clear and concise account of how a marine aquarium may be set up, stocked, and kept in good order, with the least possible expenditure of time, trouble, and patience, and the smallest possible percentage of failures. In fact, if the directions are implicitly followed, the intending aquarium-keeper ought to suffer very few reverses of fortune.

Before commencing to prepare the tank, however, let us consider the past history of the art of aquarium-keeping, in which the principles were discovered which now guide our actions when setting up the tank; for we are much more likely to be

B

THE MARINE AQTJARIFM.

successful if we master tlie scientific principles involved before we begin.

In the year 1774, a celebrated chemist named Priestley discovered the gas known as oxygen. This gas he afterwards found to be given off by plants under certain circumstances. Ingenhousz soon afterwards found out that the leaves of plants exposed to the light of day gave forth oxygen gas. Ellis, in his “Treatise on Atmospheric Air” (p. 57, et seq.), considers that he disproves this hypothesis. At the third meeting of the British Association for the Advancement of Science, held at Cambridge in the year 1833, Professor Daubeny made a communication respecting experiments on this subject, which satisfied him that in the decomposition of carbonic acid and the evolution of oxygen, the infiuence of the Vegetable would serve as a complete compensation for that of the Animal, Kingdom.

In the year 1837, Mr. Ward made a report to the British Association “ On the Growth of Plants in Closed Cases ” ; and at the end of this report he “directed the attention of the members to the development of animal life upon the same principles.” He was “ quite certain that a great number of animals would live and thrive under this treatment.” In his treatise, published in 1842, he states that “the animal and vegetable respirations might counterbalance each other”; and in a lecture delivered by Dr. H. S. Ward before the Royal Institution, he states that Mr. Ward in 1841 established, in a capacious earthenware vessel, an aquarium for fish, plants, &c. : “ In this vessel, which contained twenty gallons of water, he placed gold and silver fish, in company with several aquatic plants. In this miniature lake — the water of which was never changed, but kept in a constantly pure state by the action of associated plants — the animals lived in a healthy condition for many years.”

On the 4th of June, 1850, Mr. Robert Warington communicated to the Chemical Society the results of an experiment which had occupied his attention for some months previously. His paper was “ On the Adjustment of the Relations between the Animal and Vegetable Kingdoms, by which the Vital Functions of both are permanently maintained,” and in the

Introduction

course of it lie demonstrated that, if fishes are placed in a jar with plants of Vallisneria spiralis (the Fresh-water Weed), they will live for an indefinite time without the necessity arising for aerating the water.

These experiments were all performed on fresh- water animals and plants; hut in the year 1842 appeared a book, by Dr. Johnston, entitled “A History of the British Sponges and Lithophytes,” in which, in a footnote, the author makes a remark which shows that he did actually form a marine aquarium on a small scale.

It seems that to Mrs. Thynne belongs the honour of first introducing marine vivaria into London. She brought some madrepores to London, from Torquay, in the autumn of the year 1846, and kept them in two glass bowls, the sea water being aerated by being daily poured backwards and forwards, and being, moreover, periodically renewed by a fresh supply from the coast. “In the spring of 1847, Mrs. Thynne sent for some pieces of rock, shell, &c., to which living seaweeds were attached, and subsequently depended upon the action of these for the purification of the water.”

Later on, in the Annals of Natural History for October, 1852 (p. 263), the late Mr. P. H. G-osse published his experiments on marine aquaria. He seemed to find in his first experiments that red seaweeds were best for the purpose, such as Chondrus crispus (the Carrageen Moss) and Iridea edulis (Dulse or Dillosk), which latter he considered the best of all. Later on, however, he considerably modified his opinion, and it is now generally admitted that the green species of seaweed flourish best in captivity.

From the foregoing explanation, the following facts become apparent as to the balance between the Animal and Vegetable Kingdoms : The gills of fishes are constructed to remove from the water the oxygen which is necessary to their existence, and which is dissolved in small quantities by that fluid. How, it is evident that if the fishes were to continue using up the oxygen, and no more were to be dissolved, in process of time the supply would become exhausted, tod the fishes would immediately perish. This is what actually happens if we introduce

B 2

THE MARINE AQTJAEIIJM.

fishes into a vessel the water in which has previously been boiled, so as to expel the air, and allowed to become cold without shaking up. In nature, the oxygen is continually supplied by the motion of the waves on the sea, or the ripples caused by the wind on the water of the pond. But besides these methods, the influence of the Vegetable Kingdom is brought into play, and under the action of light (not necessarily direct sunlight) the plants in the ditches and ponds, and the seaweeds in the ocean, are continually taking up the carbonic acid gas formed by the respiration of the fishes (which, being pernicious to animal life, would be another agent in their destruction) to form their leaves, stalks, &c., and in its stead giving forth pure oxygen, which, dissolving in the water around, keeps up the supply needed by the animals. Thus, then, both parties are mutually useful to each other, and the balance of subaqueous existence is satisfactorily maintained, as far as respiration is concerned.

In Mr. Warington’s experiments, a cause of difficulty to him was the fact that the plants would not continue to thrive for a long time without some of their leaves decaying; and this, rendering the water impure, was detrimental to the life of the animals in his tank. This difficulty was, as usual, overcome by going to the fountain-head, and observing how the difficulty was overcome in the gigantic aquaria existing in nature. He found that pond snails were especially fond of decaying vegetation, and therefore, on introducing a few of these into his tank, the cause of difficulty was at once removed. What he did in his fresh- water tank by the introduction of pond snails we do in our marine tanks by the introduction of marine snails, the habits of which will be described when we come to them in their proper order.

Mr. Gosse’s experiments, detailed below, were undertaken contemporaneously with Mr. Warington’s, though neither knew what the other was doing. At first he suffered many misfortunes, as his books testify, but eventually his perseverance met with the reward it deserved ; and in his “ Handbook to the Marine Aquarium,” he states that he had at the time of writing a marine aquarium stocked with all sorts of sea

INTRODUCTION.

creatures, whicb. bad not been disturbed, nor even tbe water removed, for three years, during wbicb time tbe water bad remained brilliantly clear.

Although I have no doubt that many of my tanks would have remained clear for an immense length of time, having, in fact, kept them for one and a half, or two years, without turning out the water, yet nevertheless, as the confervse naturally grow on the rocks to an enormous extent during that time, and the stones, &c., at the bottom get dirty from continued use, I prefer to clear out the tank about once yeurly, and replace the water by fresh, the stones composing the rockwork being well scrubbed, to remove adhering vegetable growth, &c.

The main principles of the marine aquarium were now arrived at, but many important improvements were yet to come. The principal of these was the manufacture of artificial sea water, to take the place of the natural fluid, which could not then be obtained from the sea in a state of purity without considerable trouble and expense. The idea, therefore, arose in Mr. Gosse’s mind that the water of the sea might be imitated successfully by adding to fresh water the salts found in solution in that of the sea.

In the Annals and Magazine of Natural History for July, 1854, Mr. Gosse published the results of his experiments in this direction, which were so interesting that I may, perhaps, be pardoned for quoting from his paper :

‘‘ The inconvenience, delay, and expense, attendant on the procuring of sea water from the coast, or from the ocean, I had long ago felt to be a great difficulty in the way of a general adoption of the marine aquarium. Even in London it is an awkward and precarious matter; how much more so in inland towns and villages, where it must always prove not only a hindrance but to the many an insuperable objection. The thought had occurred to me that, as the constituents of sea water were known, it might be practicable to manufacture it, since all that seemed necessary was to bring together the salts in the proper proportions, and to add pure water until the solution was of the proper specific gravity.

“ I took Schweitzer’s analysis, but as I found there was a

THE MARINE AQUARIUM.

slight difference between his and M. Laurent’s, I concluded that a very minute accuracy was not indispensable. Schweitzer gives the following analysis Brighton :

of lOOOgr. of sea water taken

Water

964-744

Sodium chloride (salt)

27-059

Magnesium chloride

3-666

Potassium chloride ...

0-765

Magnesium bromide

0-029

Magnesium sulphate

2-295

Sulphate of lime

1-407

Carbonate of lime . . .

0-033

999-998

“ The bromide of magnesium and carbonate of lime I thought I might neglect, both from the minuteness of their quantities, and also because the former was not found at all by M. Laurent in the water of the Mediterranean, and the latter might be found in sufficient abundance in fragments of shell, coral, and calcareous algse, thrown in to mate the bottom of the aquarium. The sulphate of lime I also ventured to eliminate, on account of its extreme insolubility, and because M. Laurent finds it in excessively minute quantity. The component salts were thus reduced to four, as follows :

Common table salt ...

Epsom salts ...

Chloride of magnesium Chloride of potassium

Joz.

ioz.

4gr.

“ To these salts, thrown into a jar, a little less than four quarts of water were added, so that the solution was of such a density that a specific gravity bulb 1*026 would just sink in it. The cost of substances was :

Magnesium sulphate ...

Id.

Magnesium chloride ...

Potassium chloride

lid.

Salt

nil.

Total, about 51d. per gallon. Of course, if a larger quantity were made the cost of materials would be diminished, so that we may set down 5d. per gallon as the maximum cost of sea

INTRODUCTION.

water thus made. The trouble is nothing, and no professional skill is requisite. — Philip Henry Gosse.”

Since the above was written several of the large railway companies have made a special and regular business of the delivery of sea water in London at about 2d. a gallon. In the country, where carriage would be expensive, recourse can be had to the salt made expressly for aquarium purposes, which has become a common article of merchandise, so that it is now quite unnecessary for the aquarium-keeper to measure out the salts himself, as it can be bought ready mixed, and when dissolved in water to the right specific gravity, as directed by the makers, furnishes sea water precisely similar in its properties to that of the ocean itself. The salt necessary is sold by all chemists, and manufactured by Southall Bros, and Barclay. The whole of the water in use at the aquarium in the Aston Lower Grounds, Birmingham (where 200,000 gallons are in constant use), and the water at the E/Oyal Aquarium, Westminster, are manufactured from this salt, a fact which speaks volumes for its efficacy.

•as-

CHAPTER II. THE tank, an© its construction

! AYING now enumerated fhe causes wMcli influence tlie formation of the aquarium, I shall proceed to give details whereby a suitable tank may be constructed in which to keep the specimens captured. The method of procuring the specimens will be given in a later chapter.

The first item to consider is the material of which the tank is to be constructed. Glass, of course, must enter into its composition, if it is wished to see the inhabitants as they appear to one another, and not simply as when looked down upon from a higher level. At the same time, glass, unless it is used with caution, has unfortunately the disadvantage of admitting too much light. If the tank is made with all four sides of glass, it must be placed in a comparatively dark situation, and this renders it difficult to see the minute details in the structure of its inmates. On the other hand, if made partially of opaque material and partially of glass, the light is kept in check, and the tank can be placed in almost any situation such as an ordinary house furnishes.

At one time it was the fashion to keep aquaria in conservatories; but this is a murderous plan to adopt, for, whatever the construction of the vessel, the light and heat are far too strong in such a situation. The warming of the water will prove almost fatal to the inhabitants, and the glare of the sun on a hot day will complete their destruction. On the other hand, warmth

THE TANK, AND ITS CONSTKDCTION.

in moderation is advantageous : tlie anemones will not open properly if the temperature gets too low. A floating thermometer, for the purpose of ascertaining the temperature of the water at any time, is sold by dealers in aquarium apparatus. Sharp frosts are particularly detrimental to the health of the occupants, and if at all exposed to the cold air, the aquarium should have a woollen covering thrown over it at night. As, however, it is generally kept in a dwelling- room where the fire is lighted during the day, the room seldom gets so cold at night as to render this precaution necessary.

And now as to the manufacture of the tank itself. It is not worth while for the visitor at the seaside to set up a glass aquarium in his lodgings, as it is not convenient to have to

convey it home on the return journey.

A better plan is to be content with several common, cheap, red earthenware pans, glazed inside, which will answer all necessary purposes, and can be left behind, when returning home, as a legacy to the landlady. The shallower these pans are, the better, but they must be thoroughly cleaned out before putting anything into them. A number of creatures can be kept in perfect happiness in pans of this sort for the few weeks that one is taking a holiday at the seaside. The pans can be rendered more natural abodes for our captives by putting into each a few stones and green seaweeds ; but this is not absolutely necessary, as, if the water is shallow, it will absorb enough oxygen from the air.

On returning home, however, something more artistic in its external appearance will be required, and this will probably take the form of a plate -glass tank, with wooden pillars at the corners. Almost any carpenter will construct a good aquarium if an exact description is given him ; or if the embryo aquarium -keeper

THE MARINE AQUARIUM.

CC a

Fig. 2. Corner Pillar of Tank, a, a, Grooves cut along the Sides.

is a good hand at carpenteiing, lie can make one for himself in the following way : — A slab of slate is procured to form the bottom of the tank, the size of which must, of course, depend on that of the future aquarium ; a good size is IJin. or 2in. thick, 30in. long, and 18in. or 20in. wide. In this slab must now be formed grooves of about iin. in depth and breadth, running round the sides at about lin. distance from the edge (see Fig. 1). Four pillars must be constructed, preferably of birch or mahogany, each 12in. in length, and two grooves, about iin. in depth and breadth, must be made down each pillar (as shown in Fig. 2), at right angles to each other. These pillars must be turned off at the end, so as to exactly fit four holes (each about lin. in diameter, and the same in breadth), which must be made to receive them, at the four corners of the slab of slate, where the grooves join. The pillars are bedded firmly in with cement similar to that described in the next paragraph, and allowed some time to set firm in their places. Next, four pieces of what is known as 32oz. sheet-glass, of the required dimensions to form the sides of the tank, must be procured. These must be bedded firmly into the grooves in the slate and pillars with cement, after which a framework must be made to exactly

fit the tops of the pillars and hold all firmly together (Fig. 3). The last touch is given by inserting ornamental knobs at the top of each of the pillars, and the tank is then completed. Its general appearance is shown in Fig. 4.

There are several points of great importance which must be carefully observed in the construction of the tank; neglect of them will be a cause of complete failure, or at any rate of

THE TANK, AND ITS CONSTRUCTION.

considerable discomfort to its owner. In tbe first place, as to the cement, the following is used in the construction of the tanks at the Zoological Gardens, and resists the action of salt water : 2 gills of litharge, 2 gills of plaster of Paris, 2 gills of fine dry white sand, f of a gill of powdered resin ; mix, sift, and keep in a dry place till required for use, when they

Fig. 4. Tank Complete, on Stand.

must be made into a paste with a small quantity of boiled linseed oil, to which a little dryer has been added; and the cement must then be used within twelve hours. It will take about a week to dry, and if left for a much longer time, so much the better. A sharp look-out must be kept on the carpenter to whom the job of making the tank is entrusted, to see that he does not use ordinary putty, as

THE MARINE AQUARIUM.

this does not withstand the action of the water in the slightest degree. Another point requiring supervision is the insertion of the glass sides, which are sometimes fastened on by abutments, like ordinary window-panes. This was actually done with a tank in my possession, and the consequence is that it leaks to this day, though every description of cement has been tried to render it watertight. The glass must be set in grooves, and the deeper the grooves, the less chance there is of leakage. The red cement used by ironmongers for cementing taps, pipes, &c., must not be used for an aquarium. It answers well for a short time, when it gives o:ff a most peculiar odour, which contaminates the water, and causes the untimely decease of the whole of the occupants, if they are not removed immediately the smell is perceived.

If slate cannot be easily procured, the bottom of the tank can be made of hard wood, with a piece of glass cemented over it when the tank is put together. The glass will prevent any leakage through the wood which might otherwise take place. The shallower the tank is, the better, for the live stock, not being for the most part accustomed to deep water, but generally being left high and dry by the receding tide, suffer from the stillness and inactivity of the water. It can be made broader and longer than described if a larger tank is needed, but a foot of water is amply sufficient for a marine aquarium.

Mr. Warington, in the first experiments referred to in the introductory chapter, and which appeared in the Annals of Natural History for November, 1853, states that he found it best to have the back of the tank of slate or other opaque material ; and afterwards aquaria were made with the back and two sides of slate, the front only being of glass. The advantage of these consists in the fact that the illumination comes from the top only, which is more natural, and the risk of breakage from various causes is lessened. At the same time, the confervse may be allowed to grow on the slate sides and back without molestation, whereas it becomes necessary to frequently clean the glass if that material is used for those parts. Mr. P. H. Gosse, however, does not recommend Mr. Warington’s form of tank, as

THE TANK, AND ITS CONSTRUCTION.

he considers that it is clumsy in construction, and that the opaque sides and hack throw the interior into an unprepossessing degree of darkness. It is certainly much pleasanter to be able to watch the animals in the tank in the holes, <fec., in which they secrete themselves, and this cannot always be done from the front of the tank. If the tank is not placed in too light a situation, no evil will result from employing glass as the material for all four sides.

If a tank, as previously described, is considered too troublesome to construct, a very good substitute may be formed by procuring a large propagating- glass, and fixing it in an inverted

Fig. 5. Propagating -GLASSES used as Aquaria.

position on an ornamental stand. Propagating-glasses can be obtained of very large size, and capable of containing up to twenty gallons or larger. They are not so well suited for seeing objects in the interior as the four-sided tanks, as the circular bend of the glass causes distortion when looked through; they have, however, the advantage that they cannot leak. Fig. 5 shows the method of constructing such aquaria.

Tanks of an hexagonal shape are preferred by some aquarium-keepers; in this case, all six sides will, of course, be constructed of glass.

Tanks are sometimes made with a dark chamber at the back.

THE MARINE AQTJARITJM.

whicli is filled witli water, as well as tlie front and inhabited portion. The advantage of this arrangement is said to be that the water in the dark portion, not being nnder the influence of light, will keep clear for any length of time, and, by means of a machine specially constructed for the purpose, the water in the inhabited part of the tank can be made to take the place of that in the dark chamber while that previously in the back portion is brought into use. If the water in the front portion becomes contaminated in any way, it is convenient to be able in so simple a manner to replace it with fresh. Besides this, it is claimed that the impure water, when contained in the dark chamber, will gradually recover its purity, and be again fit for use. A section

of a slope-back tank, as introduced by Mr. W. A. Lloyd, is shown in Fig. 6.

My own experiences with a tank constructed with a dark chamber have been the reverse of satisfactory, as I invariably found that the water contained in it became unfit for use, and contaminated that in the inhabited portion of the tank. However, this was possibly due to the cement with which the tank was constructed, which had a greater effect on the shut-up portion of the water, as there was no escape for the emanations given off by it.

It is a good plan, though not absolutely essential, to have a cover made for the tank, in order that dust, &c., may be kept from falling into the water. If a cover is to be added, it should be formed of two pieces of glass of the same breadth as the top of the tank, and each about lin. shorter than half its length. These should be placed on the top so that there is a space about 2in. wide in the middle between them, in

Fig. 6. Slope-back Tank. A, Inhabited Portion ; B, Dark Chamber; C, C, Holes through which the Water Circulates.

THE TANK, AND ITS CONSTRUCTION.

order that air may be able to penetrate to the surface of the water. Unless the tank is kept in a very dusty situation, they are not wanted, as the dust soon sinks to the bottom, and does no barm to the inmates.

If a little extra expenditure is not objected to, a fountain can be arranged in the centre of the tank, which, by continually agitating the water, will keep the inmates in a more lively condition. The tube from which the jet springs can be hidden in a tall mass of rock rising above the surface of the water in the centre of the tank. It can be fed by a reservoir connected with it by a small indiarubber tube, the reservoir being hidden in a corner of the room, or, if an ornamental vessel is used, placed on a bracket. Of course, the higher the reservoir is, the higher the jet will be, and the more rapidly will the cistern be emptied.

If a fountain is considered too elaborate, a disturbance of the water may be brought about in a simpler manner by suspending over the tank an ornamental flower-pot or bellglass, with a sponge in the hole at the bottom. The sponge must be perfectly clean, and pushed so tightly through the hole that when the flower-pot is fllled with water it will run through in a quick succession of drops. The cord by which the flower-pot is suspended should pass over a pulley, so that by pulling the other end the flower-pot can be hoisted high in the air. Every morning the flower-pot should be filled with water dipped from the tank, and hoisted to its full height. The water then falling from a considerable height into the tank causes a splashing, which is highly effective. If neither of these plans can be adopted, the water can be agitated at intervals with a stick, and syringed occasionally with a glass syringe.

The inside of the tank should receive four or five coats of varnish, to keep the water from rotting the woodwork or becoming contaminated with the lead of the cement. As to its external adornment, this, of course, depends on the taste of the owner. Green and white look very well for a time, but the white soon gets very dirty, and when the tank has been cleaned out a few times it becomes necessary to paint

THE MARINE AQUARIUM.

it again. Nothing looks better than black and gold, or chocolate and gold, as the dark colour of the outside shows ofB, with great effect, the brilliant greens of the seaweeds and the gorgeous colours of the sea-anemones within.