7/27/2019 Management of the Freshwater Aquarium

1/4

Management Of The FreshwaterAQUARIUMThe common freshwater tropical fish is a hardy

creature and on the whole adapts very well to the

environmental changes to which it is subjected in theaquarium. This type offish is kept by thousands of

aquarists who have never measured the hardness orpH

of the water in their fish tanks, but to keep the more

delicate species or to breed the more difficult egg-layershe aquarist may have to modify the environmental

conditions. A basic understanding of water chemistry

will help him to carry out these modifications

successfully.

WATERParadoxically the source of fresh water is the sea.

The sun causes evaporation from its surface which, as

water vapour, rises into the atmosphere and forms

clouds. When clouds cool, their water vapour may beprecipitated as rain which picks up various impurities as

t falls through the atmosphere. These are very few if the

rain is falling on rural areas but over towns it picks upcarbon dioxide, sulphur dioxide, hydrocarbons, tars and

dust particles.

Once on the ground the water may dissolve

chemicals from the soil and the rocks through which it

passes. In limestone areas the water will dissolvecalcium salts and become hard (temporary hardness) or

may dissolve magnesium salts and become hard(permanent hardness). The main quality that most people

notice about hard water is that it will not lather soap

properly arid that it furs up kettles, but from the fish-keeping point of few, some fishes prefer soft water, for

example killifishes and characins, whereas others, such

as the Australian Rainbow (Melanotaenia nigrans) and

he Lake Nyasa cichlids, prefer hard water.Public water supplies which come from deep wells

are usually hard; water which comes from surfacereservoirs on moors and mountains is usually soft. In the

process of purifying water for human consumption thepublic water companies subject the water to a number of

chemical and mechanical processes. Minute amounts of

some of these chemicals remain in the water but the onlyone of importance to the freshwater fish keeper is

chlorine, added to most public water supplies as a

disinfectant. Chlorine in the free state disperses if leftstanding in the aquarium for twenty-four hours and

fishes, therefore, should not be put into newly filled

aquaria. Most freshwater tropical fish keepers use tap

water and this is satisfactory for keeping most fishes.

some species, however, and this is mentioned in

catalogue section under the appropriate entry, the wmust be soft or in rarer cases hard to keep

fishes in the best condition and to breed th

successfully.

Hardness can be measured in three different un

darks degrees (grains of calcium carbonate CaC

per UK gallon); German degrees DH (parts of C

per 100,000); or in parts per 1,000,000 of CaCO3

pre

in the water (ppm). The latter scale will be uthroughout this book. For comparative purposes 14 p

is approximately one darks degree or 0-8 DH.

CLASSIFICATION OF WATER BY PPM

SCALEDescription of water ppm

Soft 0-50

Medium soft 50-150

Hard 150-300

Very hard Over 300

Local water companies will supply informationthe hardness of the water in their area.

Gravel containing limestone or limestone rockw

will increase the hardness of water in the aquarium.

aquarist can measure the hardness of his tank water

the E.D.T.A. (Schwarzenbach) Method. This test cancarried out by any aquarist who has studied sim

chemistry at school. Chemicals for this test are availa

from most suppliers of laboratory chemicals.If the local water supply is hard, soft water may

obtained by collecting rainwater in plastic contain

from glass or plastic roofs via plastic pipes, providthe aquarist lives in an area with relatively unpolluair. Metal roofs or pipes may cause contamination. H

water can be softened by ion-exchange resins giv

demineralized water, or very expensive distilled wmay be purchased. Temporary hardness may

removed by boiling the water and filtering off

precipitated calcium carbonate. These soft waters better aerated for a few hours before placing fishe

them.

The acidity or alkalinity of the water he use

another chemical factor very important to the aquar

7/27/2019 Management of the Freshwater Aquarium

2/4

This depends upon the concentration of hydrogen ionspresent in the water, of which the pH value is the

measure. Neutral water has a pH of 7, strong alkalis a

pH of 14, and strong acids a pH of 1. Water for fishkeeping is within the limits ofpH4 topH 9.

Most fishes which prefer soft water also prefer it to

be acid and water may be acidified by adding peat. It is

not recommended to add the peat directly to the tank asalthough it sinks to the bottom after a few days, it is

easily swished about by the fishes; it is better to add thepeat to the aquarium filter. Use a good sphagnum peatmoss and boil it in soft water for five minutes. Squeeze

out and discard the surplus water (this contains excess

humic acid from the peat) and put the peat in the fbetween two layers of filter wool. Running the f

gradually acidifies the aquarium water.

There are a number of fishes which live at mouths of rivers, in coastal waters and estuaries, wh

the water is brackish. Some authorities recommend

addition of one teaspoonful of salt (NaCl) per gallon

water when keeping these species in the aquariExamples of such fishes are the Scat or Ar

(Scatophagus argus), the Green Puffer Fish (Tetraofluviatilis) and the bumble bee fishes (Brachygobspecies).

Glass Catfish (Kryptopterus bicirrhus)

EQUIPMENT

Tanks - The best shape for fish tanks is rectangular with

he length two, three or four times greater than the depth.This gives the most common size of fish tank as

24x12x12 in (60x30x30 cm), although larger sizes

36x12x12 in (90x30x30 cm) and 48x12x12

(120x30x30 cm) are also common. The smallest for a community of small fishes is 18x10x10

(45x25x25 cm). Tanks of this shape offer a large surf

7/27/2019 Management of the Freshwater Aquarium

3/4

area in relation to depth and allow carbon dioxideexpired by the fishes to be given off to the atmosphere

easily.

Smaller tanks can be moulded completely in glass or

plastic but the large tanks have angle iron or stainlesssteel frames into which the glass is fixed. The angle iron

must be painted to stop it rusting. The upper surface of

he angle iron on which the tank cover rests is mostsusceptible to rust and a good technique to prevent this is

o rub down the paint on the top surface as soon as a newank is bought and to paint the bare metal with two coats

of a cold galvanizing paint, finishing off with two coatsof good enamel paint in the same colour as the rest of the

ank. The stainless steel and nylon-coated angle iron

anks are both trouble-free in this respect. Homemade,all-glass aquaria, in which synthetic bonding agents are

used to fix the glass together, are another recent

nnovation.

Always put a glass cover on top of the tank; as wellas preventing fishes leaping out and evaporation, it stops

dust from gaining access. There are various tank coverswhich can be-placed on top of the cover glass to househe lighting arrangements.

Heating The majority of tropical fishes are happy at a

emperature of 72-78F (22-26C). Most aquarists use

he conventional immersed heater and separate immersedhermostat to provide this controlled temperature. The

mmersed thermostats are of two main types; one is

completely submersible and can be used in very shallow

anks but has to be taken out of the water to alter itssetting, and the other has a control at the top which

projects over the top of the tank. This type, therefore,

cannot be completely submerged but alterations to itssetting are easily made. External thermostats are also

popular these are either stuck or fixed by a stainless

steel clip to the side glass of the aquarium. They have the

advantage that their setting can be easily altered.

In recent years a few aquarists have used a base

heating system employing the metal-encased electric

heater used for greenhouse heating. This heater is placed

about 2 in (5 cm) under the tank and is connected to an

external thermostat, thus avoiding wires or heaters insidehe tank. Combined submersible heater-thermostats are

gaining in popularity.

Thermometers These are basically of two sorts; thoseusing the bimetal strip mechanism or those using alcohol

or mercury. The best type for the aquarium is a mercury

hermometer with the scale marked directly on the glass.Nevertheless, the experienced aquarist develops the habit

of touching the front of the tank with the back of his

hand, for with practice he can tell if the temperature isright thermometers have been known to go wrong.

Lighting Ordinary light bulbs, allowing 25 watts square foot of water surface area, for eight to twe

hours per day will give adequate lighting. The length

time depends upon the amount of daylight falling ontank and the plants the aquarist wants to grow.

Fluorescent lighting is becoming popular and in rec

years tubes emitting light of special wavelengths h

been specially developed for aquarium use. There hbeen criticisms of these tubes and the latest idea is to

both a fluorescent tube and incandescent bulbs at same time. Although fluorescent tubes are m

expensive initially than ordinary bulbs, in the long tthey are more economical because of their gre

efficiency and longer life.

Aeration and filtration Aeration by passing a streamair bubbles through the water helps to oxygenate

mainly by agitating the surface and allowing a be

exchange of oxygen and carbon dioxide. It also help

cause circulation of water within the tank. A good streof bubbles is easily produced by using an electric

driven pump and an air stone. The only real advant

of aeration is in tanks which are overcrowded and

normal aquarium should not need this aid.

Filtration filters from the water of the aquarium

particulate matter suspended in it and thus helps to k

the water crystal clear. However, not all fishes lik

crystal clear tank; many of the catfishes, for examlike a layer of sediment on the bottom. If the fi

material contains active charcoal some of the o

chemicals, including waste products produced by

fishes, are also removed. Modern filters help providbrisk circulation of water in the tank which fishes fr

running water enjoy but those from still water dislike.

Filters are of two main types, the box filter in whdirt is removed from the aquarium and the under gra

filter in which the sediment is sucked down into

gravel and subsequently broken up by bacterial actSome aquarists believe under gravel filters interfere w

the growth of aquarium plants.

PLANTS

One of the advantages of tropical freshwater tanks is the aquarist can grow plants in them. The function

plants in the aquarium is to provide decoration hiding places, and to give shade in some areas of

tank. Although plants give off oxygen during

daylight hours, this oxygen is small in proportion toamount that is transmitted through the surface layer o

properly shaped aquarium.

The genus Cryptocoryne consists of a number

favourite aquarium plants. They are bog plants in t

natural condition in South-east Asia but they also g

7/27/2019 Management of the Freshwater Aquarium

4/4

very well when submerged. One of the most popular is

C. affinis, which can grow up to 12 in (30 cm) tall. C.

beckettii is another similar plant but not as fast growing.

C. blassii, which is a very intense dark red under the leaf,s a more recently discovered Cryptocoryne, growing in

popularity. Most of the members of this genus do notnsist on bright light but do better in soft acid water.There are a number of small-sized species such as C.

nevillii, which only grows to 2 in (5 cm).

The genus Echinodorus comes from America and

also contains broad-leafed plants. E. paniculatus, theAmazon Sword Plant, is a popular species, but needs

more light than the Cryptocorynes to grow well.

There are a number of fine-leafed plants such as

Cabomba caroliniana and Myriophyllum brasiliense

which are very attractive but in my experience either

grow so well that they continually need thinning or nevergrow at all.

The species with grass-like leaves, Vallisneria

spiralis and Sagittaria species, for example, are also

attractive and popular plants. Both genera grow well inwell-lighted aquaria with ordinary aquarium gravel as

compost.

The floating or top plants such as Lemna species(Duckweed) orSalvinia species do not grow well under

artificial light. The two species of the genus Ceratopteris

(Floating Fern), however, do very well under artificial

ight and their roots and leaves are very useful as a placefor the Anabantidae to anchor their bubble nests.

DECOREvery tropical fish hobbyist should have one tank

which he sets, up with the intention of creating a

beautiful and attractive piece of furniture in his home.

This tank should be at least 24x12x12 in (60x30x30 cm)and preferably larger so that he has scope for

aquascaping.

For this furnished aquarium it is a good idea to pthe ends and back of the tank black on the outside

provide a background which sets off the colours of

plants and fishes. Choose an attractively coloured graof a particle size of about 1/8 3/16 in (3-5 mm),

even though the gravel is sold as well washed, alw

wash it again. Choose your rockwork carefully; i

possible to buy rockwork but it is far better to find yown on the mountains, on rocky shorelines or

mountain streams. My furnished aquarium has sobeautiful red sandstone rocks found on the shore ofIsle of Skye. Do not use limestone rockwork in y

tank.

Plants are now needed to set the scene for the fishAquascaping is a very personal choice and I prefer to

only Cryptocorynes they do not require exces

light, they grow reasonably slowly so that the picture

the tank remains unchanging, and there is not constant necessity of having to thin out plants as w

faster-growing species. It is a good idea before setting

a furnished aquarium to have a look at other aquaritanks and at show tanks at major fish shows to find what appeals to you.

Finally the fishes are added, preferably all more

less of the same size and chosen so that they will all together peaceably. It is a good idea never to have

one fish of a species; if you have a few they alw

stimulate each other to better colour and more interesbehaviour. It is also advisable to have one species m

numerous than the rest, one of the small tetras,

example, such as the Cardinal Tetra (Cheiro

axelrodi) or Glowlight Tetra (Hemigrammus gracilis)these species shoal together so well. Include some l

bearers Red Platies (xiphophorus maculatus)

Swordtails (x. helleri) look well against the blbackground and also a couple of Sucking Loac

(Gyrinocheilus aymonieri). These are not chosen

their looks but because they will act as vacuum clean

and keep algae from growing on the glass and plants.Fishes are best fed daily, and at the same time

hobbyist can check that they all look well and heal

and also on the temperature of the water and that it lo

clear. About every three to four weeks the front gmay need to be scraped with a razor blade scrape

algae are found growing there. From time to time it m

be necessary to siphon off any collection of mulm onbottom and to top up the water to replace evapora

losses. This is a lot less care and attention than m

other pets require and fishes do not suffer damage if unattended for two to three weeks when the aquaris

away on holidayfishes in good condition come to

harm if left without food for this period of time.

Tropical Freshwater plants - 1 floating fern; 2 Cryptocoryne;

3 Amazon Sword; 4 Cabomba; 5 Valisneria