Aquariums— Getting Into the Swim by Diane G
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Aquariums— Getting Into the Swim By Diane G. Elliott i^ well-maintained aquar- ums—from familiar rectangu- ^% ium makes an attractive lar tanks to more fanciful addition to a home, office or shapes such as hexagons and classroom and can provide globes—is available to the hours of fish-watching enjoy- aquarist. The selection of a ment. Numerous species and particular aquarium shape is varieties of ornamental fish partly a matter of esthetics, are available to suit almost but not all aquariums of the any budget and taste. Modern same water capacity have the aquarium products have made same fish-holding capacity. ornamental fish-keeping in- The area of water exposed creasingly simple. to the air is perhaps the most A basic knowledge of the important factor for determin- principles of aquarium main- ing the number of fish an tenance can help to make an aquarium can safely hold. A aquarist's fish-keeping experi- shallow 15-gallon tank with a ences enjoyable and reward- large air surface area can hold ing. The following discussion more fish than a tall 15-gallon focuses on general procedures tank with little surface area. for setting up and maintain- The best size of aquarium ing a freshwater aquarium, to select depends on your but some of the general prin- budget, personal preference, ciples apply to marine aquari- available space, and—perhaps ums as well. most important—the types of A bewildering array of fish to be kept. In practice, fol- glass and Plexiglas aquari- lowing initial setup, routine maintenance required for a Diane G, Elliott is Fishery Biolo- large aquarium is about the gist, National Fisheries Research same as for a small one. Center, Seattle, Wash. Furthermore, rapid (and unde- Aquariums 361 ANIMAL HEALTH Marie T. Sebrechts Home and office aquariums are extremely popular in the United States. About 20 million American homes have aquariums of all sizes and shapes. sirable) fluctuations in envi- available in a rainbow of ronmental conditions (temper- colors, thanks to a process ature, for example) are less that coats gravel particles likely to occur in a larger vol- with non-toxic colored mate- ume of water than in a small. rials. Natural gravel is also available. All aquarium Setting Up gravel, even that labeled as Clean an aquarium with tepid prewashed, should be rinsed water and salt only, no deter- thoroughly with water to re- gents or soaps. After rinsing, move silt. Unrinsed gravel move it to its final location be- may cause cloudiness of the fore filling with gravel and water, and the suspended par- water. Avoid locating the ticles may irritate the gills of aquarium near strong heat or fish. strong drafts, near sources of For an attractive display, toxic fumes, or in direct sun- about two pounds of gravel light. The latter will bring ex- are recommended for each gal- cessive algal growth. lon capacity of the aquarium. Aquarium gravel is now The gravel bed is generally 362 Keeping Fish Healthy ANIMAL HEALTH sloped (for example, from fish falls in the range between about 3 inches deep at the pH 6 and 8.6. Many plants rear of the tank to about half prefer a neutral or slightly al- an inch deep at the front) so kaline pH. Simple pH test kits solid wastes will collect at the accurate enough for aquarium front of the tank for easy re- use can be obtained at pet moval by siphoning. Perhaps supply stores, and buffer the best way to fill an aquar- chemicals for adjusting pH ium with water without dis- also can be purchased there. turbing the gravel is to pour Water hardness also can the water slowly into a bowl be measured with an inexpen- placed on the gravel. sive test kit. Hardness is a Water used directly from measure of the total dissolved the tap often is not satisfac- salts, principally calcium and tory for aquarium fish. Most magnesium, in the water, and municipalities chlorinate their is frequently expressed as the water supplies, and chlorine is total amount of calcium car- toxic to fish. Chlorine can be bonate present. Soft water, neutralized easily and made water with low concentrations safe for fish by adding sodium of dissolved salts, is usually thiosulfate, which is available acidic; and hard water is alka- in pet supply shops under var- line. ious trade names. Some fish species prefer soft water while others prefer Adjusting pH hard, but none thrive in dis- Water pH may need adjust- tilled water. Some salts must ment. The pH is a measure of be present for proper physio- the hydrogen ion (H"^) concen- logical functioning. Salt mix- tration in the water. The tures for increasing the hard- greater the hydrogen ion con- ness of very soft water are centration, the lower the pH available at aquarium supply value. A pH value of less than shops. 7 is acid, a pH value of 7 is Decorations selected for neutral, and a pH value an aquarium are largely a higher than 7 is basic or alka- matter of personal choice. line. Many non-toxic ornaments The optimum pH for a such as plastic plants are sold particular aquarium will de- by aquarium supply shops. pend on the types of fish and Plastic plants generally plants kept. The preference of are realistic in appearance most freshwater aquarium and are particularly useful for Aquariums 363 ANIMAL HEALTH Be careful in selecting rocks and driftwood for decorations, as they can contain soluble substances harmful to fish. (Fish in center are clown loaches, Botia macracantha, popular and peaceful fish from Asia.) aquariums housing plant-eat- ever, as some rocks and wood ing fish. However, many contain salts or other soluble aquarists prefer to grow live substances, such as copper, plants. Some aquarium plant which may be harmful to fish. growers now supply plants in Seashells and shell grit, small pots or cushions impreg- sometimes used in place of nated with a supply of slow- sand, are occasionally ob- release fertilizer, so that served in freshwater aquari- plants will obtain an adequate ums. These materials dissolve nutrient supply even in a new in the water, making it too aquarium. hard or alkaline for many fish species. Books on aquarium man- Rocks, Driftwood agement frequently contain In addition to plants, mate- suggestions and diagrams for rials such as rocks or fresh- arranging plants or other dec- water driftwood, if water- orations. An often-stated rule logged or weighted, make of design is that taller plants attractive aquarium decora- and other tall decorations tions. Exercise caution in se- should be placed toward the lecting such decorations, how- back and sides of the aquar- 364 Keeping Fish Healthy ANIMAL HEALTH ium, with smaller plants and be followed by disease. Most short decorations towards the tropical fish prefer tempera- front. Leave some open swim- tures generally within the ming room for the fish. Some range of 70° to 80° F (21° to decorations such as rocks are 27° C). Aquarium tempera- easier to arrange when a tank tures can be maintained eas- is empty. Others such as ily through use of thermostat- plants are easier to manipu- ically controlled submersible late when the tank is at least heaters. Aquarium thermome- partly filled with water. ters are widely available. Light is needed for aquar- An aquarium filter is one ium plants. An aquarium re- of the most useful accessories. flector or hood fitted with a Many filter types are avail- light serves several purposes able. Some are placed under even if live plants are not the aquarium gravel and use grown in the aquarium. A full the gravel as the filtering me- reflector prevents excessive dium. Others are contained in evaporation and heat loss small boxes which fit in a cor- from the tank, prevents fish ner inside the aquarium. from jumping out (and cats Some pump water to a filter from jumping in), and pro- box or canister outside the vides lighting for an attrac- aquarium. All filters use a fil- tive display. tering medium such as the Either incandescent or above-mentioned gravel, acti- fluorescent lights may be vated carbon, clay beads, glass used. The initial cost of flu- wool, or synthetic fiber pads. orescent lights is generally Often a combination is used. greater, but they are less ex- Aquarium filters serve a pensive to operate. Each watt variety of functions. Besides of fluorescent lighting pro- drawing off suspended irritat- vides about three times the ing particles from the water, light given by one watt of they can remove ammonia tungsten filament lighting. that is excreted by fish as a Fluorescent lights designed waste product and certain specifically to enhance plant other dissolved chemical im- growth are available. purities from the water. Some of this water purification is Heaters, Filters achieved by chemical means: Temperature changes of more activated carbon removes than a few degrees may cause chlorine and clay beads re- shock, which frequently may move ammonia, for example. Aquariums 365 ANIMAL HEALTH Helpful Baeteriâ is also wise to merely rinse A mechanism known as bio- and retain some of the old fil- logical filtration is more im- ter medium when cleaning a portant than chemical filtra- filter in an established tank, tion in many types of filters. as a total change of filter me- During the first two to three dium will result in loss of the weeks after a new aquarium beneficial bacterial popula- is set upj populations of bene- tions in the filter. ficial bacteria become estab- Besides their water purifi- lished in the filter medium. cation functions, many filters The first bacteria established serve to aerate the aquarium (members of the genus Nitro- water—largely by increasing somonas) convert toxic ammo- water movement and gas ex- nia excreted by the fish to an- change at the air-water inter- other compound, nitrite.