Caring for your Fish

(Note: includes non-native fish) Fish are very relaxing and beautiful to look at and many species are kept for these reasons. They are suitable pets for people living in flats or other confined areas, but for people with
plenty of outdoor space an in-ground fish pond can enhance a garden setting.

Whether kept in an aquarium or pond, a great deal of care is required in looking after fish properly.

Choosing your Fish

The type of fish you keep will depend on the amount of space you have, and the amount of money you wish to spend on their purchase and the equipment associated with their care.

There are two broad categories of aquarium fish; freshwater and saltwater (marine) - and within each of these categories are coldwater and tropical varieties. Coldwater fish are suitable for coldwater aquariums but
tropical fish need heated water; outdoor pond fish are normally of the freshwater-coldwater type.

Choose cheap fish to begin with (because these are generally the easiest to keep) and buy only healthy specimens; be sure to purchase your fish from a reputable dealer (dead fish in the sale tanks indicates poor health). Beginners should start with a small freshwater aquarium and a few coldwater fish. Saltwater tanks are more difficult to manage than freshwater. Choose hardy specimens such as goldfish; there are many varieties of goldfish but only some are available in Australia. Coldwater marine fish such as leather jackets, breams and small flounder are also cheap and easy to keep.

Tropical freshwater fish suitable for beginners include platties, sword tails, guppies and mollies. Be sure that you know how to keep fish properly before buying tropical fish because they are very sensitive to poor water quality and temperature fluctuations. Tropical marine fish suitable for aquariums include clownfish, wrasses and tropical seahorses. Seahorses can be difficult to feed properly as they often require specialised food.

Never keep incompatible fish together as some may eat others. Also, be careful with aggressive fish such as Angel fish. They can be very aggressive towards each other, particularly if the space in the tank is limited. For advice talk to the pet shop and also contact your local Aquarium Society. Members are usually very helpful with advise, equipment purchases and sourcing of suitable fish.

Care for your Fish

� Housing

A fish tank should be an appropriate size for the number of fish held. If a non- aerated aquarium or outdoor pond is used, allow three centimetres of water surface area for every three square centimetres of fish (including the tail). A tank should be rectangular; fish bowls have a small water surface area and therefore limit the amount of oxygen entering the water. In addition, for each centimetre of fish you will need about five litres of water regardless of whether the tank is aerated or not.

It is now useful for glass tanks to be glued together with silicone sealant rather than having a frame as in the past. If a frame is used, marine aquariums must be framed with aluminium or stainless steel to prevent damage to the frame by the saltwater. Either way, the glass from which the tank is made must be thick enough to withstand the weight of the water.

Freshwater should be allowed to stand in a stainless steel or plastic container for 24 hours before use, to allow dissipation of chlorine (common in tap water). Seawater is best made up from bottled water or tap water with the addition of special sea-water mix available from aquarium shops.

� Establishing an Aquarium

  � Place the empty aquarium and stand on a flat solid surface in a well-lit position but not in direct sunlight.
            Direct sunlight will heat the tank water too much during the day and it will cool too much at night and as a
            result your fish will suffer stress diseases. Direct sunlight will also cause too much algae to grow and the
            tank will be difficult to keep clean.

  � Remember that one litre of water weighs one kilogram and there is the additional weight of the tank,
            stand and other equipment. The floor surface you have chosen must be able to support this total weight.

  � First, half fill the aquarium with water (clean tap water is suitable). If a bottom filter is to be used, install it
            at this stage. Then place sand on the bottom with pebbles and stones for decoration and to provide
            hideaways for the fish. Anchor in some water plants which will help oxygenate the water.

  � Complete the filling of the tank to within five centimetres of the top. If you have purchased active fish, or
             they are likely to be disturbed, they may jump out of the tank, so cover the aquarium with a glass top that
             is raised sufficiently to let air in.

  � A water filter operated by a small electric submersible motor will help to keep the tank clean, but if your
            fish are being fed too much food, thus excreting too much, algae will still overgrow in the tank.

  � The same motor can operate an aerator that pumps tiny bubbles of air into the water. These aid in
            circulating the water (which helps with oxygenation, since most oxygen exchange takes place at the
            surface). Bubbles also show that the filter is working properly. Many filters use a combination of charcoal
            filters and fine sponge filters to remove solids. These will need to be regularly cleaned and replaced. You
            can stock the tank with 40% more fish if an aerator is used.

  � For tropical fish a heater and thermometer are also needed to keep the water at the right temperature
            (22� C - 24� C for tropical and marine fish and 15� C - 20� C for coldwater fish). The effects of central
            heating and other forms of room heaters should be considered. Water temperature in tanks should be
            checked daily and maintained within a range of 5� C of the optimum temperatures.

Let the newly filled aquarium stand for about 3-4 days before buying your fish. Fish are usually sold in a plastic bag and this should be floated on the surface of the tank water for about 30 minutes to allow the water and fish in the bag to reach the same temperature as the water in the tank. This way, fish will not get a shock by being moved to water at a different temperature. A sudden temperature shock of even a few degrees can kill the fish. After this time, add tank water very slowly to the bag to allow the fish to acclimatise to the tank water (and thus prevent osmotic shock). Then decant the fish into the tank.

New aquariums take about 2 - 3 weeks to 'settle down' after the fish have been added. During this time tanks should be tested daily for nitrates and ammonia (using kits which can be purchased cheaply). Nitrates and ammonia are very toxic to fish, however they are converted to more harmless nitrates by the action of "nitrifying bacteria". Once the bacteria reach equilibrium in the tank, they will convert the nitrates and ammonia as it is produced. The plants use the nitrates in the water.

Change about a quarter of the water every week whether it is dirty or not. Be very careful to ensure that the replacement water is at the same temperature as the tank (to within two degrees) If the tank is particularly dirty replace about 1/3 of the water at once, clean the filter and then remove and replace a quarter of the water each day until it is clear again. Carefully monitor the nitrate and ammonia levels.

Never overfeed the fish. Add just enough food for the fish to eat over a five minute period. Carefully siphon off any uneaten food from the tank floor.



� Establishing an Outdoor Pond

Fish ponds are best if in-ground and made of cast concrete, although some prefabricated cement constructions and some butyl rubber liners are suitable. Where plastics are used, ensure that the supplier warrants them suitable for use with live fish as many plastics are toxic. The minimum depth of available water must be 30 cm., but it is wise to have even deeper sections so that fish can reach cooler water areas. As with aquarium fish, the number placed in a pond will depend on the surface area of the water and whether or not the water is filtered and circulated.

Adequate aquatic plants must be placed in the pond to help remove nitrates and phosphates (which cause algal growth) and to provide shelter for the fish and a place for eggs to be laid. Algae and plants generate oxygen during the day, but absorb oxygen at night. On still warm summer nights they can easily remove all of the oxygen and kill the fish. To avoid this, ensure that pond pumps run at night when there is no wind to ruffle the water. Rocks must also be strategically placed to provide both good shelter and for decorative purposes.

Ponds are best sited out of direct sunlight in order to control algae growth. Watch for predator birds if setting a pond near large trees. A water filter system is essential to remove algae and other impurities and the system should be designed so that one-quarter of the water is replaced each week this is easily achieved by establishing a deliberate leak in the water filtration system of appropriate volume. Newly poured concrete ponds, and new butyl rubber liners should be filled with water and allowed to stand for four weeks. After draining and cleaning it is safe to refill and stock with fish.

� Feeding

If your fish are kept at a constant temperature in the aquarium you should feed them every day. Allow just enough food for the fish to feed for about five minutes. Supply a variety of dried food (flakes), frozen food (brine, shrimp, daphnia) fresh food (earthworms, tubiflex) and green food (algae and water moss) all of which is available from aquarium shops. Do not overfeed fish as the uneaten decomposed food will make the water smelly or clouded and the fish will die.

Pond fish require feeding every two days in summer and once weekly in winter. Buy suitable pellets from a pet supplier. Trout pellets are generally too rich in protein for fish such as carp and goldfish, and can cause pollution problems in the pond.

� Health

The principal causes of death of fish in an aquarium or pond are overstocking and polluted water. As fish must live permanently in the area where they eat and excrete, the tank must be cleaned regularly to remove this material which will foul the water. Learn to recognise normal fish behaviour, and know what to do if the fish begin to behave in an unusual way. For example, fish gasping on the surface is a sure indication of a fouled tank or pond with little oxygen left. Other signs of infections and diseases are change of colour, swollen skin or eyes, a swollen belly, a rotting tail or white spots over the body of the fish. Check with your veterinarian for advice.

Remedies for some common problems such as white spot, fin rot and fungus are sold from aquarium shops. Prevention is obviously better than cure, but where a fish becomes sick it is best to remove it to a small treatment tank so that the other fish do not become infected. Seek advice about treatment from the local Aquarium Society or veterinarian.

Remember that tobacco, dog flea treatments and garden and household sprays such as insecticide can pollute the aquarium or pond and kill the fish. Read the labels carefully, seek advice and cover the tank before spraying.