39 top tips for fishkeepers


Here are some of our favourite fishkeeping tips. Whether you're a newbie or a seasoned fishkeeper, there's something here for you!

13 tips for new fishkeepers

1. Be patient

If you live your life at 100 mph, then fishkeeping may not be the hobby for you. Keeping fish properly involves building complex ecosystems that harness useful bacteria to recycle waste products. This takes time to achieve and can be frustrating at times. A new tank may take six weeks or more to mature and within that time, stocking levels should be low. Furthermore, a water test may reveal that your tank is not safe for fish for much longer periods, and you may wonder why you took up fishkeeping in the first place.

The good news is that if you do it properly, you shouldn’t ever experience water quality problems again, and once mature, you can keep those fish that were on your wish list from the start.

Be patient and it will pay dividends. Rush things and it might all go horribly wrong.

2. Stock slowly

This is crunch time. If you put too many fish into your aquarium too soon, they may die. The best way to combat this "new tank syndrome" is first to cycle your tank properly. This means getting a colony of bacteria growing in your filter before you add fish, so that they are ready to consume the waste as soon as the fish are added.

This fishless cycling can be done by adding maturation agents to the water, which add live bacteria and their food, making it safe. Once fish are added, the bacteria levels will expand to cope with the extra waste, but if you add too many fish too soon, the bacteria will not multiply in time and ammonia and nitrite will be present in the water, poisoning the fish.

3. Don’t overfeed

Food manufacturers recommend feeding three times per day, but if you have a new tank, this is often excessive.

If you are watching your water quality or stocking a new tank, one feed per day is usually enough. Only once you have a full quota of fish and your tank has been running trouble-free for a few months should you increase the feeding, and even then feed little and often.

How much is a pinch? Good question, because depending on the size of your fingers and the type of food you are feeding, amounts will be vastly different. Ask your retailer to demonstrate how much they feed to each of their fish, so you get a more accurate idea.

4. Don’t overstock

This is a really easy mistake to make. There is so much choice in the shops and they crowd their fish, so why can’t you? The answer is that overstocked aquariums suffer many problems like lack of oxygen, inadequate filtration and an increased risk of disease.

Territorial fish like most cichlids will become more aggressive, and you will have to maintain your tank much more frequently. Growing fish can even be stunted by a lack of space, and all your fish may look chewed and dog-eared as a result of overcrowding. If you want more fish, the only answer is another tank.

5. Choose function over novelty

When choosing a tank, get one that is the right shape. Spheres, columns, hexagons and corner tanks do not have the surface area or swimming length that a standard rectangle provides. It may not look as funky, but your fish will be much happier, and equipment will fit more readily into a rectangular-shaped tank.

The same goes for gaudy decoration. Most tropical fish are adapted to a wild environment, and that means muted colours like browns, greys and greens. Offer bright blue gravel to a brown catfish, and it will turn pale in an attempt to blend in. Use white gravels and all your fish will look pale and washed out. Natural coloured sands and gravels will make fish feel at home.

6. Buy as big a tank as you can afford

The essential bit of kit if you want to keep fish indoors. If you are new to keeping fish, you really should buy as large a tank as you can, and that means 60 cm/24” or over in most cases. The reason for this is that larger bodies of water are more stable than smaller ones, but a larger tank benefits you by enabling you to keep more fish. Most community fish are better in groups, but there are hundreds to choose from. A larger tank means you get to keep more of the fish that you see in the shops.

7. Find a good retailer

This may be crucial to the success of your new tank. A good aquatic shop will not only provide the equipment and livestock that you need, but more importantly they can offer trustworthy advice. A good retailer thinks about the long-term effects of what you do and won’t sell you unsuitable livestock because it will ultimately come back to them, so it is also in their interest to get your tank running smoothly. Check out our list of the UK's top shops, as voted for by PFK readers in our 2011 reader's poll.

8. Join a fish club

Have you ever thought about joining your local fish club? Some clubs may seem a little antiquated, but they all contain one important factor, and that is experienced fishkeepers. A good club will have hundreds of years worth of combined fishkeeping experience and expertise, and they are a good place to pick up home-bred fish and unusual species as well.

If you specialise in a certain type of fish, you could join a national club that caters just for them. Choose cichlids, goldfish, catfish, livebearers, anabantoids or killifish to name just a few, and you will enter a world of people who are fanatical and approachable about the type of fish that you love.

9. Keep the easy stuff first

As frustrating as it may seem, if you are inexperienced in keeping fish, you really should opt for hardy, non-aggressive species first. Hardy first fish will feed readily and acclimatise to most types of water, even water that may be slightly too hot or cold. Platies and danios have stood the test of time and may be hardier than goldfish in some circumstances. They may even breed.

Hardy fish do not have to be kept long term, and an understanding retailer will often part-exchange if you wish to upgrade to say Discus or Malawi cichlids in time.

The advantage of keeping hardy fish initially is that you can practise feeding and water changes on them, and it won’t end in disaster if at first your methods are a bit crude.

Keep Discus in the wrong sort of water and you will witness their untimely demise.

10. Make time for maintenance

Aquariums can look very attractive, but without some work on your part, they can quickly turn into an algae-filled swamp. Set aside some time every day, every week and every month for different levels of maintenance.

Daily maintenance may take just a few seconds, checking that equipment is functioning and the front glass is clean.

Weekly maintenance may involve wiping cover glasses and topping up evaporation losses, or even a small water change.

11. Make notes

Keep a diary detailing everything that happens with your tank. List the set-up date and daily water test results, and keep a list of the fish that you bought, and when you bought them.

A diary can be handed over to a retailer in the event of problem solving, and may give clues as to what happened and when.

If your fish breed, your diary will provide a record of how long the eggs took to hatch and what the pH and temperature were when your fish spawned. This record will be useful if you wish to breed that species again, or to pass on advice to other people.

12. Be prepared

When keeping fish at home you must be prepared for all eventualities. A net is absolutely essential as you may need to move fish for any number of reasons.

If you keep tropicals, a spare heater is a good idea, and if you regularly experience powercuts, consider a battery-powered airpump to provide the fish with essential oxygen.

We often view our fish in the evening, when the aquatic shops are shut. Make sure you have enough frozen food and medications in case you spot a sick fish. Spare fish bags are a good idea for transporting fish to and from shops, and the polystyrene transport boxes are very useful, even for keeping fish in short term.

Ensure you have enough tapwater conditioner for emergency water changes and a divider if your fish start to fight.

A spare tank is a good idea and these can double up as quarantine or hospital tanks. Above all, make sure you have enough test kits.

13. Set realistic budgets

Make sure you can afford to properly accommodate the type of fish that you wish to keep. A 60 cm/24” set-up may cost £80, but fully stocked and decorated, with test kits and cleaning equipment may take the initial set-up into the hundreds.

If you want a planted set-up remember that higher-tech tanks with high lighting levels, CO2 injection and frequent nutrient dosing will require a lot more maintenance and cost than a lower-tech tank, so bear this mind before you even buy the gear.

Marine set-ups are another good example – set a £500 budget for a small reef tank, and £1000+ for a larger one. If you aren’t realistic and cost cut on the way, you may never end up with the desired result.

Big fish are long-lived and expensive to keep, due to large equipment and tanks, and feeding bills. If you can’t keep a big fish long term, don’t buy it as it may be unsaleable when adult. Food bills for big fish can run into the hundreds over the course of a year.

5 tips on buying fish

14.  Ask questions

Before you buy any fish, make sure that it is suitable for your tank. Find out its maximum size, preferred water conditions and feeding requirements first, and never buy on impulse. Make sure that the fish will mix with your existing ones, and find out whether it can mix with its own kind.

15. Choose healthy fish

This is a skill that is learnt, so if you are unsure, take an experienced fishkeeper with you when getting your first fish. As sometimes shops don’t spot minor afflictions, look really carefully for signs of whitespot or bacterial infection.

Fish should have bright eyes and all their fins intact, and if they have scales, they should be fully scaled with none missing. Active fish should be exactly that, swimming in an upright position and looking for food. Ask your retailer to feed them in front of you, and don’t be afraid to point out the one that you want.

16. In car travel

It is important to pack your fish properly when travelling by car. Tell the staff how far you will be driving so they can provide the necessary oxygen, but also ask if they can provide you with a polystyrene box. These boxes are used to transport fish all over the world, for days at a time, and keep the fish warm and secure.

If there is empty space inside the box, use air-filled fish bags or a towel to wedge the bags in so they stay in one place. Seal the box with sticky tape and place in the boot, again wedging it in so the box won’t slide around.

If you can’t get a polystyrene box, stand the bags in a cardboard box or a bucket to keep them upright and stop them sliding about. Place a towel over the top to block out the light and keep the warmth in.

With no boxes or buckets, prop the bags up in a secure place. One possibility is the rear passenger’s footwell – slide the front seat back so that it holds them securely.

If a passenger is entrusted with their care, the bags should be kept between their feet and not held on laps. Do not inspect the fish while travelling – keep them in the dark for the length of the journey.

If you are worried about the fish getting cold, climate control is the best option. If you only have a fan, gentle warmth will be fine.

Don’t place the fish directly under hot fans as this will raise the bag temperature quickly, depleting oxygen.

And don’t hang carrier bags in the boot of your car. Fish can be killed by the constant swinging and knocking that any journey would provide.

17. Go straight home

This may seem obvious to most of you, but a high percentage of people still go off and do other things while their fish are in transport. Sealed polythene bags hold limited amounts of oxygen, and fish pollute the bag water from the moment they are placed into it.

If you have other plans, arrange to collect the fish last, or inform the member of staff who is packing the fish. They can pack them more lightly, in larger bags with more oxygen.

18. Acclimatise

Once you get the fish home, the aim is to give them a smooth, stress-free transition to your aquarium. After being in the dark while travelling, the fish should be kept in dark conditions, and not blinded by tank or room lighting.

Turn the lights off and float the unopened bags on the surface of the water. If there are several bags, syphon some water out of the tank so that the displacement does not cause it to overflow. How long you float the bags differs from expert to expert, but the aim is for the temperature of the bag water to equalise with that of the tank. This usually takes about 20 minutes.

Undo the bag or cut the knot off and roll down the sides to make a floating collar. Gently introduce some tank water every few minutes until the bag contains mostly tank water. This will equalise the water chemistry. Next catch the fish in a small net, release into the tank and discard the bag water as it will be polluted with fish waste. The whole process should take under an hour.

Once in the tank, it is important to observe the new fish. Give it half an hour or so before you turn the lights back on, and check that the fish are not being bullied by the older tank residents. Small amounts of chasing are OK and should subside, but biting or ceaseless attacking means removing the new fish or the attackers, or separating them with a divider.

Feeding small amounts when you introduce new fish can help, as the existing residents will be too preoccupied with the food to notice, or single out, the newcomers. Moving all the tank décor is particularly effective with Malawi cichlids as they all become ‘new’ fish and start off more or less equal.

A period of quarantine in a separate tank is always advised, and water conditions and temperatures can be equalised that way.

9 equipment tips

19. Get the right advice

If you are starting out in this hobby, you need to be steered in the right direction so that you get keeping fish right the first time.

Once again, finding a good aquatic shop is crucial to your success, and by building up a relationship with the people who work there, you will get honest, trustworthy advice.

PFK can help you there too, with a team of unbiased experts in our Fishkeeping Answers section.

20. Buy quality kit

Fishkeeping is a long-term thing, and you need to invest in the right kit. Filters and heaters need to be well made and reliable, for a failure will mean disaster. Buy decent brands and go on recommendations by PFK and other hobbyists. Buying the cheapest product available may mean a false economy in the long term if it struggles to do what it is meant to do, or isn’t very easy to use.

21. Shop around

With so many places to buy your equipment, the aquatics industry is a buyers’ market, meaning that by shopping around, everyone is forced to keep their prices low – and you win by getting the best deals.

Some shops will price match online prices, but don’t expect them to be very happy if you treat them as your showroom, taking their advice, pulling apart their product – and then buying it online.

When buying online watch out for the price of postage and packaging, delivery times and returns policies, and compare the pros and cons with that of just popping into your local shop.

22. Go smaller

This is relevant mainly to heaters, because if a heater fails in the ’on’ position, it may cook your fish. Purchase two small heaters and if one goes, it will take longer to overheat the tank and you will hopefully notice before you sustain any casualties.

Another area that is commonly overdone is flow. Not all fish come from raging torrents, and the constant flow can stress or even kill some species. Check the natural requirements of all your fish, and adjust flow accordingly.

Many anabantoids like Siamese fighters and gouramis, come from still water, so gentle filtration will suffice.

Fish fry need air-powered foam filtration at most.

23. Go bigger

This is particularly relevant to filters and protein skimmers. Any piece of equipment that has a vital cleaning role needs to be man enough for the job. Choose models that will cope with your tank volume and then some – at least 50% more in most cases.

Cichlids, messy fish, crowded tanks and even goldfish will break the rules when it comes to standard filter recommendations and what they can and can’t do.

If you have an existing filter that you wish to keep on using, double up and have one at each end.

24. Check power consumption

The cost of electricity isn’t getting any cheaper, and with green issues looming all around us, it helps to do our bit. Check the wattage of any pump that you buy, and choose a reliable model that also offers low running costs.

This goes for pond pumps, too, as a large model will cause a dent in your electricity bill if it runs 24/7.

For marines, lots of pumps with high wattage also means heat, possibly leading to expensive chilling methods, and even more energy consumed.

25. Maintain your equipment

Detritus and algae can play their part in shortening your equipment’s lifespan. Regularly clean filters, and that includes impellers, shafts, inlets and outlets.

If you wash sponges regularly in tank water, they will last longer as they shouldn’t ever get to the point where they become so clogged that they collapse and become misshapen.

Clean light tubes, reflectors and cover glasses for maximum light penetration.

26. Don't overcomplicate

You can have too much of a good thing, and sometimes a fascination with equipment will lead to a deviation from the original point – enjoying fish.

Take a step back and think hard about the equipment that you really need, and the equipment that you don’t. Syphons, algae pads and nets are essential, but what about the other stuff that you have accumulated? Do you really need battery vacuums, nitrate removers and other gadgets, or can they be done with in exchange for a bit more regular maintenance?

27. Get a light timer

This simple bit of kit is so useful to the fishkeeper. Excess light can cause algae in all types of aquariums, and if you rely on your own switching on and off, and forget, or can’t get to the tank for what ever reason, it is likely that you will get algae as a result.

Live plants and corals have adapted to the constant sunlit day and dark night cycle of the tropics, so by plugging your lighting into a timer you can simulate it, providing your livestock with what they need.

Multiple lighting can mean multiple timers, so dawn, dusk and moonlight can be simulated by getting blue light to come on before and after the main lights.

No special aquatic timers are necessary, and a short trip to your local DIY store will offer you all you need. Simple analogue timers will suffice, but digital models are also available.

6 health tips

28. Test water

So many health problems can be traced to adverse water conditions. If your fish start to look sick, test the water. Anything more than ‘0’ in readings of ammonia or nitrite is unacceptable, and even low underlying levels can cause stress and disease to your fish.

Check the pH to see if it has changed from the norm. A rising pH can make ammonia more toxic, and a sinking pH can crash to dangerously acidic levels. If you treat with medications but still expose your fish to less-than-perfect conditions, they may not respond to treatment.

29. Isolate

The standard community tank is not the best place for your ill fish to get better. In most cases, you will have to treat the whole tank to try to reduce the chances of cross-infection, but it isn’t effective for a number of reasons.

Firstly, plants and bogwood soak up medications, diluting the dose, and efficient biological filters also play their part in breaking it down. Even aquarium lights will degrade treatments, making them less effective. Isolate your fish in a separate tank.

An isolation tank does not need to be big or pretty, it just needs stable water conditions and a mature filter. Don’t use any chemical media like carbon, and an air-powered foam filter will suffice in most cases. As long as the tank holds water and is clean, it will be fine to use as a hospital tank. Ambient light is fine for the reason listed above, but low light will also cause less stress to the fish.

Extra aeration is important as medications strip the water of oxygen. Décor can be a simple flowerpot for cover and maybe a plastic plant. Fit a tight lid as irritation from parasites and reaction to medications can cause jumping.

30. Seek expert advice

If you are still not sure what is wrong with your fish, remember that time is of the essence, and you will need to get it diagnosed and treated within a day of finding out about it. Any longer and it may be too late.

Take a photograph and show it to your retailer, or in the worst-case scenario, take one of the fish in for inspection.

For large fish, experts may be able to take a skin scrape and examine it under the microscope. This should give a definite answer. For small fish, a diagnosis of whether the problem is parasitic or bacterial should be enough to point you in the direction of the right medication.

31. Get a good book on health

There are different ailments that afflict aquarium fish, and it is important that you diagnose each one correctly. Bacterial infections may not respond to parasite treatments and vice versa, so get a good book, with pictures, that will help you find out what it is.

32. Proper use of medications

Using medications is not something that we should take lightly. Most are made from dangerous, sometimes carcinogenic, chemicals that should not come into contact with our skin if we can help it. Use latex gloves to protect the hands and if you are using raw formaldehyde or Malachite green, goggles and a mask are a good idea.

Keep them locked away and out of the reach of children, and check the dates that they need to be used by. Seek expert advice if considering mixing any treatment.

Never overdose as it could kill weakened fish, and make sure that you know the volume of water that you are treating. Read the instructions carefully. Only redose on the advice of the manufacturer.

Beware of copper-based medications when keeping some fish. Elephantnose, Black ghost knifefish and stingrays (above) are particularly sensitive, as are scaleless fish like some loaches.

Marines like mandarins and Harlequin tuskfish should be treated with similar caution, and invertebrates like shrimp and snails will be harmed or killed by copper. That is why it is used as an effective treatment on parasitic invertebrates.

33. You can treat prophylactically!

If it ain’t broke, don’t fix it! That phrase works in most walks of life, but in fishkeeping, treating before there is a problem can be helpful. Take Guppies or Dwarf gourami as an example. These fish have become weakened and disease-prone of late, so mixing them with other species in your community tank straightaway may mean them introducing or catching something. Isolate them before introducing to the main tank, treat, and observe, and it may stop problems further down the line.

Discus benefit from being wormed, whether you think they have them or not, and pond fish are naturally more prone to disease at certain times of year.

Don’t treat prophylactically too often though, as this gives parasites greater resistance and they respond less readily to future treatments.

6 tips for more advanced fishkeepers

34. Visit your fish’s natural habitat

For many people, this is the ultimate fishy experience. If you want to thoroughly research what your fish need, then you can’t beat actually visiting their natural home for yourself.

Once there you can take temperature and pH readings, take photos of the habitat for aquascaping purposes, dig around and find their actual food and have a go at catching some fish yourself. You will find out so much in a short time and be able to provide a lot more for your chosen fish when you get back. You’ll get a good suntan, too!

35. Breed something that hasn’t been bred – yet!

Sadly, there are hundreds of species that have to be wild caught, or are so new to science that no one knows how to get them to reproduce in captivity. Research their requirements as much as you can, change water regularly and feed lots of different foods, but above all, be patient.

Try some old tricks like raising temperature, cooling or lowering the water level, and cover your bets by adding mops, caves and other devices for catching eggs or having eggs laid upon.

If you think your fish are getting frisky, get some brineshrimp on the go for the day any fry hatch. If you’re successful, let PFK know as you may be the first in the country – or even the world – to breed a new fish in captivity.

36. Watch that RO water!

The benefits of using RO water are obvious – soft water, less algae, less phosphate and nitrate, but it shouldn’t always be used neat. Pure RO water has been stripped of its minerals to the point where it is vacuous. It will seek to pull minerals and salts from other media like gravel, and if kept totally pure in a substrate-less tank, it can even pull salts out of fish.

Something else to watch out for is a pH crash. RO has no buffers to stabilise pH, yet biological filters produce acids and will bring pH down. This isn’t always a gradual process, and already slightly acid water with a pH of say 6, can rapidly crash to pH 4 or lower in the space of a day.

Those who use lots of softwater, like many Discus keepers, will do well to get a digital pH tester like a pH pen, or better still, a permanent pH read-out attached to the tank. Even if you require a very low pH, add electrolytes, minerals and occasional buffers to stop it getting too acid, and make it habitable for your fish.   

37. Dechloraminate

Many of us now have our water treated with chloramines. This has implications for our fish as chloramines is better at killing bacteria (both good and bad) than chlorine.

Chloramine doesn’t vent off like chlorine either, so letting your water stand is a waste of time. Always use a tapwater treatment when adding new water, that treats chloramine and chlorine.

38. Build your own filter

You know how it works and you know what it consists of, so why not try making your own? If you have lots of tanks and a limited budget, home-made filters can be really effective. Trickle filters can be made out of virtually anything from plastic crates to plant pots, as water enters at the top and trickles

through to the bottom.

Pack them with anything from hair curlers to stickle bricks and they will break down ammonia very effectively, and oxygenate at the same time. Stick them over the top of the tank, connect them to a pump outlet and you are away.

Box filters are also dead easy. Get an old ice-cream tub or pop bottle, drill holes in the bottom and stuff it with media of your choice. Either stick a pipe down the middle for air power, or a powerhead on the top, and it’s done!

39. Make your own food

If you get through lots of packets of frozen food each month, you could try making your own. Put some prawns, spinach and garlic into a blender, add gelatine to stick it all together, and place in the freezer. You can make your own ideal size blocks and feel safe in the fact that you know exactly what you are giving your fish.

Check the supermarket shelves for anything fishy that you can’t already get in your local aquatic shop. Look for crab, squid and shellfish, and the best food for large freshwater predators is freshwater fish, not saltwater fish, so if you can afford it, chop up some trout and feed that.

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