Learning topic: Provide advice on animal breeds and species

General characteristics and requirements of fish as pets

This topic looks at two main areas relating to keeping fish as pets:

selecting suitable fish and plants

managing the environment for pet fish.

Selecting suitable fish and plantsIn a commercial environment, such as a pet shop, it is important to be able to provide quality stock to consumers. Acquisition, maintenance and delivery of this stock is addressed in the following material. The ability to recognise stock that is suitable for resale is essential in order to avoid dissatisfaction or frustration amongst customers.

Desirable characteristics of stock

The characteristics that are considered desirable will vary depending on the species and, in some cases, the individual specimen being examined. Desirability of stock purchased must be based on how keeping that stock will affect the retailer (you) in the running of the shop and how reselling the stock will affect the customer. Selling stock which is overpriced or unsuitable for the customers’ needs will eventually lead to poor customer satisfaction and eventually loss of repeat business.

Desirable characteristics of fish include the following:

absence of signs of disease

absence of signs of behavioural problems

good body condition

good colour

physical activity at a level appropriate for the species

particular patterns or intensity of colour

body shape

appropriate body size or 'age' for the retail market

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species rarity

ease of keeping

high market demand.

There may be a presumption of health in some cases if the source of the fish is a long-term, trusted supplier.

Body condition

The assessment of body condition will vary according to the species of fish. As a general rule, the fish body shape should closely resemble the type shape that is usually depicted in fish encyclopaedias. The fish should not appear obese—see under assessment of health—or malnourished. Examples of fish that may appear malnourished after shipping are the species that are known for their fussy eating habits, for example the knife fish, discus, barramundi.

Poor body condition may be a sign of starvation or disease. If it is the former, then this can be corrected by good nutrition. However, this will take time and cost money. What appears to be very good condition may in fact be a sign of gravidity (pregnancy). While this is not a problem in itself, it can cause health problems in some species if they are transported whilst gravid. For example: black mollies commonly abort and sometimes die if disturbed when they are near to delivering their young.

Colours

Colour will vary with species, sexual status, age, body condition, disease status and, in some cases, the environment in which the fish are being kept. All these factors must be taken into account when assessing the colour of a fish. As a general rule, the brighter the colour, the better for resale.

Most consumers prefer brightly coloured fish. It should be borne in mind that intense colour can be a sign of disease and, in some cases, may indicate that the fish is very near to death.

One other factor to consider is that some unscrupulous breeders use chemicals or drugs to artificially enhance the colour of fish and it is probably unethical to encourage this practice by purchasing this stock.

Physical activity

Physical activity also varies greatly according to species and any inspection of stock must take this into account. It is easy to see if a normally active species like tiger barbs (see picture below) are unusually inactive, but it may be very difficult to make a valid assessment of sedentary species like spiny eels.

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Learning topic: Provide advice on animal breeds and species

The type of activity should be examined, as well as the level of activity. Activities that are not usual for the species being inspected should be noted, as they may be signs of disease or poor husbandry. There is obviously an overlap between types of activity and behavioural patterns.

Patterns

Patterns of colour are one of the prime determinants of resale value in some species of fish. In any species where there are many sub-types—for example, koi carp, Discus—colour intensity and patterns are of great importance.

There are many different patterns of colour in koi carp and some of these patterns are deemed much more valuable. If the buyer is to be involved with any of these potentially expensive fish, then they need to acquaint themselves very well with the different patterns and the demand that exists for each pattern.

With fish like discus new patterns may emerge fairly regularly and it is often the new patterns that are the most sought after. This means that when the sub-type first appears there is increased demand and prices are high but as the market becomes flooded, and more breeders are successful with the new type, the prices can crash.

Body shape

The body shape of many fish is also a factor in resale value. Body shape can either refer to the individual's relationship to 'type' standards for that species—similar to the show standards for body shape in dogs and cats—or to the individual having specifically shaped appendages, for example, lyre tailed mollies have a caudal fin shaped like a lyre.

Cases where a maximised standard body type is desirable will only be a factor if the consumers that you are selling to are educated in show standards for members of the relevant species. The higher price for these

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individuals can only be justified to a consumer that can appreciate the quality of the stock.

Specifically shaped appendages will be sought after by consumers that don't need to be particularly interested in show or breeding standards for the fish; the unusual or attractive body shape is the selling point by itself.

Body size

Body size must be suitable for resale. As a general rule, most buyers prefer to purchase fish that are near adult size.

There are some advantages to purchasing fish that are near adult size:

Generally speaking, adult fish have a better chance of surviving transport and handling.

Adult fish are far easier to sex.

If any defects are likely to develop, they will be more apparent on adult fish.

Adult fish will cost the consumer less to get to breeding size.

Adult fish will have developed all their adult characteristics of colour, appendages, etc.

However, there are disadvantages to purchasing adult fish:

They have reduced life spans. This can be significant with some species such as Zebra Danios, where the natural life span is about 12 months and it may mean that the consumer may only have the fish for several months before it dies of 'old age'!

Adult fish are larger and therefore invariably cost more. This may lead to consumer resistance.

Adult fish eat more and therefore cost more to maintain before sale.

The sexual behaviour of some species means that adults must be kept separate and this can consume space and money. For example, adult oscars (see picture below) can be aggressive, particularly if paired and usually are kept in separate tanks.

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Learning topic: Provide advice on animal breeds and species

Some adult fish are less attractive than young members of the same species. For example, young black widow tetras are darkly coloured and the patterns are very definite. As these fish become adult, their colours fade and become less attractive, making them harder to sell on.

Some species are too large as adults to keep comfortably in typical display tanks found in commercial pet shops or aquariums. Barramundi are a good example of fish that grow very large and are usually only sold as juveniles.

Rarity

Sometimes the very existence of the species is enough to justify purchasing for resale. Many consumers will pay premium prices for fish that are known to be rare or in short supply. This may relate to species or sub-types of a species.

Particularly good individuals of species also fall into this category. It obviously requires a detailed knowledge of the market demand and the species being inspected to make a judgment about resale value of these fish.

Careful consideration must also be given to the source of rare fish. For example, have they been obtained legally by the supplier or are they endangered?

Examples of fish that might attract high resale values include:

some types of discus

many different species of rare catfish, eg Peppermint Bristlenose

some types of African cichlids

quality specimens of fish considered 'lucky' by some people—saratogas, arowanas, some catfish, etc

some killifish (see picture below)

other assorted species and sub-types.

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Ease of keeping

The ease of keeping the species impacts on the commercial operator because a species that is very difficult to maintain will cost more in time, tank set up, special foods etc and could cost a great deal if it dies.

Difficult species may be harder to sell on as only experienced fish keepers are usually interested in them—or ignorant inexperienced fish keepers. Paradoxically, sometimes the difficulty of keeping a fish is what attracts some people to that species.

There is a challenge in maintaining and perhaps breeding such difficult animals. Obviously, there is an ethical obligation to warn customers of the difficulties of keeping these species.

High market demand

High market demand can lead to species being bought in greater quantities than normal. Market demand is very complex (see later under plants) but can be artificially stimulated eg by particular species or groups of species being profiled on 'life style' programs.

Managing the environment for pet fishPet fish are kept in tanks and you’ll need to provide advice regarding:

lighting

heating

filtration

plant choice to your customers.

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Learning topic: Provide advice on animal breeds and species

Lighting

The lighting requirements of fish vary with the species. The types of lighting available today are many and some forms of lighting can be very specialised and expensive.

Some authors suggest that fish can benefit from some indirect sunlight each day. This can cause problems with algal blooms and overheating of the tank. With the advent of the large range of artificial lighting available today, the use of sunlight is probably not necessary.

Lighting serves several purposes:

it makes the fish more visible and the tank more attractive, ie it has an aesthetic purpose

it simulates daylight for the fish

it can be used for, and is essential for, plant growth.

Types of lighting

The most common lighting used today is fluorescent—it is relatively inexpensive and doesn't radiate as much heat as incandescent globes. More expensive lighting includes various forms of arc lighting. The range of fluorescent globes is large, with many intensities and wavelengths represented.

Factors that need to be considered when selecting lighting include the following:

The wavelength produced must be appropriate. Are plants to be grown or is the light just to illuminate the tank?

The deeper the tank the more intense the lighting needs to be—a 60 cm deep tank requires either a stronger tube or more tubes when compared with a 40 cm deep tank.

Light fittings are commonly plastic. Older fittings may be metal and these need to be used with care near water. If the metal comes in contact with the water it is possible for the surface to oxidise and heavy metals to leach into the water. With marine tanks, metal fittings should never be used as they will corrode very rapidly.

The lighting requirements of individual species need to be addressed. Many of the fresh water species that are kept come from rivers and lakes with heavily shaded edges. Therefore, in the wild, these species would receive only four or five hours of direct sunlight each day. If lighting is to be applied for 10-12 hours a day, as is very common in many tanks, then these fish must have somewhere in the tank to be in the shade. This is one of the uses of plants.

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One of the drawbacks of intense lighting is that it promotes algal growth. This is considered undesirable by many aquarists, even if it seems to do little harm.

Some fish cannot stand intense lighting and if feeding is only carried out when the lights are on, these fish are likely to starve to death.

Heating

The most common heaters used are designed to be placed inside the aquarium and operate using a thermostat. The thermostat is set to the required temperature and once that temperature is achieved the heater turns itself off. Heaters of differing power are available and it is important that the correct one is chosen for the tank. Even though they are thermostatically controlled, a powerful heater can overheat a small aquarium.

Points to consider:

Aquarium heaters should never be turned on when out of the water

Aquarium heaters should be handled with care in the water—they generate a lot of heat and can burn.

Heaters should not be in contact with plants or plastic items, eg filter attachments.

The thermostat should not be assumed to be accurate. A thermometer should be used to double-check the water temperature.

Large tanks may require two heaters. This allows the burden of heating the aquarium to be shared and can prolong the life of the heaters. This is good practice anyway because it means that there is a back-up if one heater fails.

Summary of heating and lighting requirements

The heating and lighting requirements are based on tank size, whether or not plants are to be grown and the species of fish to be kept.

Below is a table summarising the tank size, surface area and water volume with the heat and light requirements:

Tank size (LXDXW) 60 x 45 x 40 90 x 40 x 30 90 x 45 x 40

120 x 45 x 40

120 x 60 x 40

Surface area 2400 sqcm 2700 sqcm 3600 sqcm 4800 sqcm 4800 sqcm

Water volume 108 litres 108 litres 162 litres 216 litres 288 litres

Heat 200 watt 200 watt 200 watt 300 watt 400 watt

Light 45 watt 50 watt 80 watt 120 watt 160 watt

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Learning topic: Provide advice on animal breeds and species

Filtration

Filtration is a huge topic and only the basic principles will be covered here.

Filters are used for several reasons:

To remove particulate matter from the water using mechanical means.

To remove toxins from the water using chemical means.

To remove organic and other waste material from the water using biological means.

To agitate the surface of the water and, therefore, improve aeration.

To provide current flow throughout the tank and decrease the chances of locally high concentrations of undesirable substances.

Types of filtration

There are three types of filtration:

Mechanical filtration This is the removal of particulate matter from the water via mechanical means. For example, trapping particles of plant material in the mesh of a medium.

Chemical filtration This is the removal of chemical substances from water, generally by using other chemicals. For example, activated carbon is often used to remove toxins from the water.

Biological filtration This is the removal of organic waste products from the water. Organic waste products are those derived from uneaten food, fish waste—urine and faeces—dead fish, plants or other once living things. The rotting of timber placed in the tank will also contribute to organic waste products. Biological filters are really an attempt to recreate what occurs in the animal's natural environment in terms of degradation and recycling of waste products.

There are three stages to this process:

1. Ammonification: Degradation by bacteria of organic material into inorganic material. One of the by products of this process is ammonia.

2. Nitrification: Ammonia is converted into NITRITE and then into NITRATE.

3. Denitrification: Nitrites and nitrates are converted into nitrous oxide and free nitrogen.

All three of the above processes require specific populations of bacteria. For biological filtration to work efficiently, it is important that populations of bacteria that prefer oxygen—aerobic bacteria—and prefer low or no oxygen, anaerobic bacteria, are present. This is why so much attention is given to the design of filters and filter media. All the different designs are

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attempts to satisfy the needs of both aerobic and anaerobic bacteria in an effort to maximise biological filtration.

Note: Ammonia and nitrite are the most toxic substances in this cycle.

Biological filtration and the bacterial population

Biological filtration is perhaps the most important aspect of filtration in any fish tank/pond. High levels of appropriate populations of bacteria are required for efficient biological filtration. It is important to realise that fish tanks are really about keeping two separate populations of organisms alive and healthy. The first population comprises the occupants of the tank. The second population comprises the billions of bacteria within the tank and the filter. The second population is vitally important for the long-term health of the first population.

How can we develop a healthy population of bacteria in a newly set up tank?

Allow natural processes to take place within the tank without any animals being introduced. This process can take four weeks or more before bacterial populations reach levels capable of detoxification.

Add a few hardy animals to the tank that can withstand relatively high concentrations of ammonia and nitrite. The production of excreta by these animals provides the bacteria with increased nutrients so their rates of multiplication are greatly increased. It is possible to reduce the time before more valuable fish can be introduced to about two weeks.

Add some bacteria laden gravel or shell grit from an established, healthy tank. It is only necessary to spread one or two handfuls evenly over the gravel in the new tank, or even place some of the old gravel within the filter of the new tank. The bacteria multiply rapidly and the waiting time for introduction of new fish can be reduced to about one week.

Add commercial probiotics to the water. These are commercially produced populations of bacteria and will rapidly colonise the tank and the filter. They may reduce the time until required introduction of fish can be done to as little as a few days.

Irrespective of what method is used, the following points should be borne in mind:

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Learning topic: Provide advice on animal breeds and species

Fish should be added slowly, ie, only a few at a time.

Even if the tank has a good population of bacteria for dealing with ammonia, the populations that metabolise nitrites and nitrates must be given time to reproduce. It is not uncommon for people to successfully add fish for 6-12 weeks only to suffer a massive loss. What has happened is that the toxins have been building up to dangerous levels, until the capacity of the bacteria to cope is exceeded. Once this occurs the toxins will build up unchecked and the fish start to be immediately and drastically affected.

The tank from which seeding bacteria are being drawn must be disease free.

Anything that affects the operation of the filter will also affect the bacterial population.

If antibiotics are used, the filter must be spared exposure as much as possible. If there is a power blackout for more than a few hours then care must be exercised with regard to the filter.

Some bacteria will start to die after a few hours and restarting the filter may pump toxins from bacterial degradation into the tank.

Summary of filtration requirements Filtration can be mechanical, biological or chemical.

All fish tanks should be considered as having a population of tank inhabitants and a population of bacteria.

A healthy bacterial population is necessary for the long-term health of the tank occupants.

Selecting plants

Desirable characteristics of plants include the following:

the size of the plant

the root system of the plant, if it has one

the rarity of the plant

the robustness of the plant species and the individual specimen

freedom from disease

the habit of the plant, ie its pattern of growth

the market demand for plant species

the physical appearance of the plant.

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