It is easy to decide that owning an aquarium would be a nice idea, but it can be difficult to know just where and how to start. These are the questions you must ask yourself first.

  • What size aquarium can I accommodate (and afford)?
  • What sort of fishes would I like to keep?
  • Small or large (aquarium size permitting)?
  • Freshwater or marine?
  • Coldwater or tropical?
  • What are their specific requirements and habits?
  • Will they live in my tap water and, if not, am I prepared to go to the trouble and expense of providing the right conditions?
  • Will they get along with each other?
  • Do I want to grow plants?
  • Will my preferred fishes eat them?

Life being what it is, you may have to compromise when it comes to your personal inclinations, but never do so when it comes to the fishes’ welfare. That must always come first.

Although considerations of expense and the space you have available may limit your options, do, if possible, let your preferred choice of fishes dictate factors such as aquarium size rather than vice versa, as keeping the species you really want is bound to increase your motivation and enjoyment. Establishing your preferences will require a certain amount of effort in finding out what species are available, making a list of those you find attractive, and applying the above questions to them. You are bound to find that some are incompatible with available space, each other, and your personal concept of a miniature underwater paradise, but the wide choice available should enable you to compile a suitable shortlist without undue trouble.

In deciding what fishes to keep you must consider how many your aquarium can accommodate. This is often calculated in terms of oxygen requirement, based on centimeters of fish (length excluding the tail when full-grown) relative to the surface area of the tank: for freshwater fishes 2.5 cm of fish per 194 cm’ (1 inch per 30 square inches) of surface (coldwater) or 2.5 cm per 64 cm’ (1 inch per 10 square inches) (tropical). For marines the formula is 2.5 cm of fish per 18 liters (1 inch per 4 gallons) for the first 6 months, then 2.5 cm per 9 liters (1 inch per 2 gallons). For some fishes, however, population density may be governed by territorial requirements, and fewer fishes can be kept than is suggested by the above formulae. Carassius auratus (the goldfish) is a coldwater fish which can be kept in an aquarium or pond, but should never be confined to a bowl or other small container.

Fish Compatibility
The compatibility (or otherwise) of fish species must always be taken into consideration before they are mixed. First of all, environmental requirements must be similar. Mercifully, few people try to mix marine and freshwater species, but many attempt (unsuccessfully) to keep brackish water fishes in freshwater aquaria. Even more fail to realize the varying degrees of hardness and acidity/alkalinity occurring in different freshwater biotopes, and that fishes from these different water chemistries do best if given natural conditions in captivity. Temperature requirements should also be similar. Some fishes come from fast-f1owing streams, others from still pools, and the needs of both cannot be satisfied in one aquarium. Some prefer rocky habitats, others jungles of plants, yet others open space; some require bright light, some require dim. All these points must be considered when evaluating their environmental compatibility.

Size and temperament are just as important.
Although not all species feed exclusively on other fishes, it is natural for larger fishes to eat smaller ones. So, except where dealing only with strict vegetarians, always ensure the smallest fish is too big to fit into the largest mouth ? and that, allowing for future growth, it will remain so. Some fishes are territorial, occupying an area which usually represents either their private larder or their intended nursery (feeding and breeding territory respectively). They are usually aggressive towards con-specifics (members of their own species) in particular, and frequently towards other species as well. They can sometimes be kept with other fishes if the latter are evenly matched (in size and temperament), but they may need their own tank.

Think about feeding.
Do you really want to keep fishes with varying specialized dietary needs, requiring you to serve a variety of foods at each meal?

  • Will the slow and steady eaters get any food at all if you include a number of fast-swimming greedy species?
  • Will that harmless but large and boisterous fish you like the look of frighten the life out of smaller, shyer tank mates?

These are all questions that must be answered. Never make any assumptions on the basis of apparently successful and uneventful cohabitation in a dealer’s tank; the fishes’ behavior may be affected by relative crowding, lack of decor, and by their age (often fishes offered for sale are sub-adult). Give them space, something to fight over, and a few months’ growth, and the story may be quite different!

Making Your Selection

Don’t succumb to your understandable impatience to get up and running this preliminary research should be regarded as all part of the fun. Patience is an essential quality to cultivate if you want to succeed, so the sooner you practice it the better! We cannot over emphasize the importance of getting everything right first time. There is no point in setting up your tank and then finding it won’t do for the fishes you want to keep; that will mean settling for second best or starting again from scratch. Get it wrong and you risk causing suffering to your fishes, not to mention wasting your time and money; what should have been a source of immense enjoyment for many years could turn into a nightmare.

Far too many aquarists set about the task in completely the opposite fashion, setting up an aquarium and populating it with whatever their local pet shop has to offer that month. Only later do they realize what they are missing when they see a fish they really like, often totally unsuitable for their aquarium. The sensible few go home and find out about their dream fish before buying it. The majority, regrettably, take it home without doing any homework, usually discovering their error the hard way upsetting for the aquarist, but catastrophic for the fishes.

The Fishkeeping Network
Apart from books, there is another invaluable source of information available to you the accumulated knowledge of other aquarists, both professional (dealers) and other amateurs like yourself. Fish keeping is a friendly hobby, and you will find that most enthusiasts are more than willing to help. If it was seeing a friend’s aquarium that stimulated your interest in the first place, don’t be afraid to go back to him or her and pick his or her brains. He or she may know other aquarists who will be only too happy to let you see their set ups and answer your questions.

Consider joining your local aquarists’ club
You will be made welcome even though you don’t yet have any fishes of your own. Such clubs exist in most large towns and cities, although it is not always easy to obtain a contact address. Local aquarium shops may be able to help; if not, most countries have a national federation of fish keeping clubs which can supply details, and whose contact address can usually be found in fish keeping magazines.

Even if you are not by nature the sociable type, there are many advantages, apart from shared knowledge, to belonging to a club. If you have fish keeping friends then you have people you can call upon in all sorts of otherwise difficult situations getting a large tank home and into place; looking after your fishes while you are on holiday;. helping out if some vital item of equipment fails at .3 am on Sunday morning. There is the possibility of spare equipment and home bred fishes at bargain prices, and perhaps the loan of extra reading material.

The Aquatic Dealer
It will also be to your immense advantage to find a good aquatic dealer and make a friend of him. You will need guidance when it comes to buying equipment, because the quantity and variety available nowadays is confusing even to the expert, and positively daunting to the beginner. He will be able to advise what is best suited to your particular circumstances, and what brands are most reliable. A good dealer is also a mine of information on fishes and fishkeeping. You may not buy all your fishes from him (he may not have what you want ,though if you are a good customer he may get it for you), but you should reward his investment of time and patience in you, his customer, by always going to him for “dry goods”. He may not be right on your doorstep, but his help will more than recompense you for any expenditure in time and travel.

So, how do you find a suitable dealer? Firstly, ask other aquarists for a recommendation. Failing that, the most important difference between a good dealer and a bad one is one of attitude. Both have a living to make, but money is the chief motivation of the bad dealer. He will rarely be prepared to spend time talking. Don’t expect him to net out a particular fish from a batch of 20 it will be too much trouble. He will grumble if you insist on a pair, even if the species is easily sexed. He will allow you to buy any combination of equipment and fishes without question.

The honest dealer, by contrast, will try to deter you from any folly, and perhaps even refuse to sell he values his reputation and integrity more than the proverbial quick buck. If he can’t answer your questions, he will get a book out. Ask for two fishes, and he will catch you a pair if they are sex-able. He will be patient and will take time to talk, even if you are a stranger who may never darken his doors again and he will probably recognize you when you do go back.

If in doubt, try going along with an outrageous shopping list of totally incompatible fishes (we suggest, for example, the oscar cichlid and the neon tetra), and let it be known that you have just (yesterday) set up a 60cm (24-inch) tank and intend introducing both to it immediately. The bad dealer won’t bat an eyelid and will get out his nets and polythene bags. The good one will likely make a choking sound? then explain the error of your ways and make an alternate recommendation