Ten Golden Rules of Fishkeeping

Author: Last updated:

There are many things to learn in fish keeping, and it can seem like an uphill struggle, but finding out more should be part of the enjoyment of keeping fish. These 'top ten' golden rules should give any fish keeper a good start and avoid some of the common problems seen time and time again.

Shoal of Cardinal Tetras

1. Don't over-feed your fish

The biggest cause of most problems encountered by new fish keepers (and often experienced ones) is over feeding. An aquarium is a 'closed' environment, so whatever goes in the water becomes part of the environment your fish are living in. Food breaks down into pollutants that are toxic to your fish, releases phosphates which encourage algae, and contributes to general waste matter, which makes the aquarium look unsightly and can encourage disease. Overfeed your fish, and the resulting increase in waste will have a detrimental effect on your water quality, causing fish to become ill, and will encourage algae and general debris, making the tank look unsightly.

As a general guide, your fish should eat everything given to them in about a minute, any food sinking to the bottom before it is eaten or left over after a minute and you are overfeeding your fish. Bottom dwelling scavengers or algae eating fish are the exception to this guide, since they will need sinking foods like wafers, and whilst they will take longer to feed, they should still eat everything in a short period. In a new establishing tank, it is best to feed just once a day, but this can be increased after a few months to follow the 'little and often' rule of feeding. Introducing a 'rest' day once a week when no feeding takes place can also help to keep your fish healthy and encourage them to search for food.

2. Regular but small aquarium maintenance

Getting maintenance right is vital for the long-term health of your aquarium yet many fish keepers tend to under or over maintain their aquarium. Basic maintenance includes partial water changes, debris removal, algae wiping, and filter maintenance and should be carried out on a weekly or fortnightly basis. It is much better to do regular low-level maintenance than occasional 'big clean' style maintenance, which can disrupt the aquarium causing a loss of useful filter bacteria, affecting water quality, and having a detrimental effect on your fishes health. Don't overdo it, but do it regularly.

3. Provide the right environment for your fish

If your fish are becoming ill, not feeding, hiding away, loosing colour, or simply not doing well, yet your water quality seems fine and the aquarium is in good health it can be rather difficult to figure out what is going on. One factor which is often overlooked yet can make a huge difference to the health of your fish is the visual environment they are kept in, by which we mean the rocks, plants, ornaments and other fish in the aquarium. If you take a small shoaling fish, which in its natural environment lives in heavily vegetated shaded streams and pools, and put it on its own in a tank with bright gravel, a few 'ornaments' and rocks, it is going to feel very distressed and is likely to become ill and even die. Take the same fish, along with several others of the same type, and put them in a tank with a natural coloured substrate, plenty of live plants, and a few pieces of bogwood, and they will all thrive, showing strong colours, feeding eagerly, and interacting with each other. Getting the environment right for the type of fish you are keeping, and choosing all your fish to be compatible, will make a huge difference to overall health.

4. Choose the right equipment for your fish-tank

Filters, lights, and substrate (gravel) can all have a direct effect on how well your aquarium does the things you want it to do. You can rarely 'over-filter' a tank, and an inadequate filter may not cope with all the wastes your aquarium produces, resulting in a slow decline in water quality, both in terms of pollutants and physical (visible) waste material. Small internal filters are often the worst and some designs that come with aquariums are truly bad, so it may be worth thinking about upgrading. For aquariums over 60cm, it is well worth investing in an external filter, which will give you much better filtration and the option to use different filter medias later on.

When it comes to substrate, you need to think about whether you want, or will want, to keep live plants in the aquarium. If you do, it is worth noting that most larger gravels are far from ideal for plants, and changing the substrate at a later date is a messy and tricky task. Taking a bit of time at the start to look at your equipment options, and perhaps biting the bullet and going for a slightly pricier option, will pay off in the long run.

5. Clean your filter in tank water

An easy and common mistake made by many fish keepers is cleaning their filter sponges or media under the tap. Chlorine and chloramines in tap water are harmful to both fish and the bacteria in your filter that perform the task of breaking down waste products. Cleaning filter media under the tap will kill a significant amount of bacteria and without those bacteria, harmful pollutants will build up in the tank, creating health problems. Always clean your filter and filter media in water taken from the aquarium, which can then be discarded.

6. Research your tropical fish

There are hundreds of fish you can purchase for your tank, and they are all different. Some fish get big, some are aggressive, some fight with similar fish, some nip fins, some hold territories, some are predatory... the list goes on. Choosing incompatible fish can cause all sorts of problems, as well as causing unnecessary suffering to your fish, and is completely unavoidable with a little prior research. Instead of buying fish 'on spec', take a bit of time to see what's available, write them down, then go home and look them up, or at least get the advice of a good retailer before you buy.

7. Add new fish to your tank slowly

A new tank needs time to mature, and for the bacteria which process wastes to develop and multiply. If you stock your tank too quickly, or add too many fish at one time, the increase in waste can be too much for the existing population of bacteria to deal with, and water quality soon deteriorates, leaving your fish in unsuitable water and at risk of health problems. Always add a few fish at a time, leaving several days between each purchase.

8. Test your aquarium water

The majority of aquarium problems have some basis in water conditions, particularly fish health or algae, so it is vital that you know about your water conditions and test on a regular basis. Water testing is relatively easy and does not require a degree in chemistry to understand so there is no excuse for not doing it - in most cases you will recoup the cost of testing by avoiding potentially serious problems.

9. Find a good local fish shop

Whilst we try to cover as much of the hobby as possible and give you as much advice as we can, you still need a good source of advice at the point of purchase, and a good retailer could make or break your fish keeping experience. As well as being a good source of fish keeping knowledge, a good retailer will genuinely have your best interests at heart - they will want you too succeed so you carry on fish keeping and keep spending money, perhaps even progressing on to bigger and better tanks. Spend plenty of time trying out different retailers and then stick to the best one for all your livestock.

10. Enjoy your tropical aquarium

Most importantly of all, enjoy your fish and your aquarium, and take plenty of time enjoying it. Fish keeping is all about recreating a miniature natural habitat in our homes and this can take a bit of work. Seeing your fish thriving and going about their business in the world you have created for them is a huge reward for the effort you have put in, so get it right as best you can, and be proud of your achievement.

Related Fishkeeping Content



Click to read the Latest Think Fish Discussions from Thinkfish users.

Tropical Fish Keeping Help and Advice
Fish of the month