Here are some commonly held myths and misunderstandings about fish keeping:

“Beginners’ tanks are small” NO: When starting out, buy the largest tank you have the physical space for.  Some homeware stores, even some pet shops, sell ‘fish tanks’ which are tiny, and which are marketed as ‘beginners’ tanks (which are quite often just as expensive as larger ones).  The bare minimum requirement for any living creature is 20 litres, and for any kind of ‘community’ you need to be looking for at least twice that amount of space.  As well as providing the physical space for your pets to grow, the more water there is, the more room for error there is too: the tiniest blip in water conditions can be devastating in a small space, but much less problematic in a larger one. 

“Cold water fish are easier than tropical” NO: Literally the only difference between a cold water and a tropical fish tank is a heater.  If anything, tropical is easier, as there are many smaller varieties of tropical fish whereas goldfish require a much larger space.  Our minimum tank size for one goldfish is 60 litres, and that is quite honestly pushing it, considering that fancy goldfish (the kind best suited to indoor keeping – common goldfish can grow to 18” long and belong in outdoor ponds) can grow to roughly the size of two of your fists clenched together. Cold water fish also give out much more waste than most tropical fish, and algae grows more freely in cold water, so it is harder work to maintain a cold-water tank.

“Gold fish do not need a filter” NO: All living creatures kept in a tank require a filter, in order for their waste to be processed so that they are not swimming around  in toxic conditions.

“Fish only grow to the size of the tank” NO: In too small a space, a fish will become stunted in its growth, which means it will live a very short and painful life, before dying long before its time.  The fish you see in pet shops (including ours) are nearly always babies.  They will grow, and when planning your set-up, you need to get an idea of their adult size, to make sure you are providing the space they need to live a long and comfortable life.  Also, don’t base your stocking plans on the number of fish you see in any shop’s sales tanks: as well as being babies, they are also only in the shop for a few weeks maximum, not for life.

What you will need:

A tank as above, the largest you have space for is best, in that it is easiest to control the water parameters in a larger expanse of water, plus once you have ‘the bug’ of fishkeeping you will inevitably want to upgrade (trust me – it happens to pretty much everyone!)  All new tanks come with a filter and lighting; most with a heater too.

A filter which may be an internal unit that sticks on the side of the tank with suckers, a trickle filter built into the lid, or an external canister.  Whichever model you go for, its job is the same: to filter the physical debris out of the water to keep it clean and clear, but most importantly to host the beneficial bacteria colonies that process the fishes’ waste to prevent them from having to swim around in dangerous, toxic conditions.  The filter is the most important part of your set-up and must be kept on 24/7 to keep your fish safe.

A heater which is set at a temperature suitable for your fish (most common tropical fish are happy between 24-26C).  It is kept fully submerged and will cut out when the desired temperature is reached, just like an oven does.  A thermometer is useful to keep an eye on the temperature to put your mind at rest (and also to help with water changes later on).

Lighting which is usually either a fluorescent tube set into the lid, or, more commonly now, an LED unit attached to the lid.  The lights are for your benefit, to help you enjoy looking at your fish: the fish themselves are not fussed whether they are on or not.  Be aware that you should not have your lights on more than about 6 hours a day, or you will be likely to get algae running out of control in your tank.  While there is nothing harmful about algae (in fact many fish enjoy nibbling it) it can look unsightly if it gets out of hand.

Sand or gravel (substrate) for the bottom which is up to you to choose.  Sand is best if you wish to keep bottom dwellers (such as cory catfish) and gravel is a bit easier to keep looking clean.  Your fish won’t be bothered about the colour you choose, so while you might prefer a more natural look, don’t be ashamed of choosing vivid coloured stuff if that takes your fancy.

Plants and décor which is again entirely down to your personal taste.  Natural plants can be nice for the fish to nibble, but artificial ones are perfectly adequate (and totally maintenance free!)

You might also like an air pump to provide bubbles for your fish to play in, but this is largely cosmetic rather than essential.