13 tips for new fishkeepers

1. Be patient when starting a new tank

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. A water test may reveal that your tank is not safe for fish prolonged periods. This may result in you wondering why you started fishkeeping in the first place.

You shouldn’t ever experience water quality problems again once you have started the aquarium properly. 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.

Related article: Setting up your fish fish tank

2. Stock your aquarium 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. That bacteria are ready to consume the waste as soon as the fish are added.

Fishless cycling can be sped up a little by adding maturation agents to the water. These add live bacteria along with their food, making it safe over time.

Once fish are added, the bacteria continue to reproduce to cope with the extra waste. If you add too many fish too soon, the bacteria will not be ready in time. This means ammonia and nitrite will be present in the water, poisoning the fish.

3. Don’t overfeed your fish!

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 tank of fish 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 your tank

This is an easy mistake to make. You may think that as shops crowd their fish, 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 will become more aggressive, meaning disputes between inhabitants become more frequent.

Growing fish can become stunted by a lack of space. Resulting in all your fish looking chewed and dog-eared as a result of overcrowding. Do you want more fish? The only answer is another tank.

5. Choose function over novelty when picking your aquarium

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 have 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

This is the essential bit of kit required to keep fish indoors. If you are new to keeping fish, you 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. A larger tank also 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 aquatic retailer

This may be crucial to the success of your new tank. A good aquatic shop will provide all the equipment and livestock that you need. But, perhaps more importantly, they can offer trustworthy advice.

A good retailer thinks about the long-term effects and won’t sell you unsuitable livestock because it will ultimately come back to them. Also, it's in their interest to get your tank running smoothly so you enjoy the hobby and continue to visit their shop. Check out our list of the UK's top shops, as voted for by PFK readers in our 2024 reader's poll.

8. Join a fish club

Have you ever thought about joining your local fish club? Fish 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. 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 from cichlids, goldfish, catfish, livebearers, anabantoids or killifish to name just a few. You will enter a world of people who are fanatical and approachable about the type of fish that you love.

9. Keep beginner friendly fish first

As frustrating as it may seem, if you are inexperienced, 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.

Danios (pictured above) and livebearers, like platies, have stood the test of time. They may even be hardier than goldfish in some circumstances.

You do not have to keep these hardy fish forever. An understanding retailer will often part-exchange your fish when to change your aquarium. Perhaps you now would like to try discus or Malawi cichlids.

The advantage of keeping hardy fish initially is that you can practise feeding and water changes on them. If something goes slightly wrong it won’t end in disaster.

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

10. Make time for aquarium maintenance

Aquariums can look 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.

You can hand your diary to a retailer when trying to problem solve. This may give clues as to what happened and when.

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

12. Be prepared for surprises when keeping fish

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. If you regularly experience powercuts, consider a battery-powered air pump 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. The addition of polystyrene transport boxes are useful, even for keeping fish in short term.

Ensure you have enough tapwater conditioner for emergency water changes and a divider if your fish begin fighting.

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 £100. But a fully stocked and decorated aquarium, with test kits and cleaning equipment may double this cost!

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. They also cost more than a lower-tech tank, so bear this mind before you even buy the gear.

Marine set-ups are another good example. Set a minimum of 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.

Large fish are long-lived and expensive to keep, because of equipment, tanks, and feeding bills. If you can’t keep these fish long term, don’t buy it as it may be unsaleable when adult. Food bills for large, predatory 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. Learn 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 whether it can mix with its own kind. Our website contains lots of information available on various species. Websites like Seriously Fish can also be extremely helpful here. 

15. Choose healthy fish

Spotting sick fish is not easy at first, 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 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 ask for the exact fish that you want.

Related article: Frequently asked questions on treating sick fish

16. In car travel

Pack your fish properly when travelling by car, as this is important. Tell the staff how far you will be driving so they can provide the necessary oxygen.

Also, ask if they can provide you with a polystyrene box. Fish get transported all over the world in them, for days at a time and remain 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. 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 you entrust a passenger with their care, all them to keep the bags 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.

Remember not to hang carrier bags in the boot of your car. Fish will die from the constant swinging and knocking that any journey would provide.

17. Go straight home after buying fish

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. While 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 you new fish

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. Aim 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. Regularly check that the fish are not being bullied by the older tank residents.

Small amounts of chasing are OK and should subside. Signs of biting or relentless attacking are not. Remove the new fish or the attackers, or separate them with a divider.

Feeding small amounts when you introduce new fish can help. The existing residents will be too busy 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.

Always try to quarantine new fish in a separate tank. You can match water conditions and temperatures easily that way as well as spot diseases.

You can also use the drip method to acclimatise your new arrivals. This is great for more sensitive species like Caridina shrimp. You can watch our guide below. 

9 Equipment tips

19. Get the right advice

If you are starting 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. 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. Submit your questions to [email protected].

20. Buy quality aquarium kit

Fishkeeping is a long-term thing, and you need to invest in the right kit. You should buy filters and heaters that are reliable and well built. A failure to these pieces of equipment will mean disaster.

Buy decent brands and check recommendations by PFK and other hobbyists. Buying the cheapest product available may mean a false economy in the long term. As you may have to buy another, more expensive, product to replace it when it stops working.

21. Shop around for the best price

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 before buying it online.

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

22. Smaller might be better

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. But bigger is sometimes best

This is extremely important for 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 of standard filter recommendations.

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

24. Checkhow much power the fish tank will use

The cost of electricity isn’t getting any cheaper. With environmental 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.

Marine tanks require lots of pumps with high wattage. These produce heat, possibly leading to expensive chilling methods, and even more energy consumed.

Related article: 38 ways to make fishkeeping cheaper!

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. 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 tank

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 actually 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 need battery vacuums, nitrate removers and other gadgets? Perhaps with more regular maintenance you'll be fine without them.

27. Get a light timer for your aquarium

This simple bit of kit is so useful to the fishkeeper. Excess light can cause algae in all types of aquariums. If you rely on manually switching it on and off you are likely to forget one day. This is likely to result in algae issues when it occurs.

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

Multiple light units can mean multiple timers. This can allow you to simulate dawn, dusk and moonlight within your aquarium.

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, wifi compatible models are also available.

6 Tips for healthy fish

28. Test water

You can trace many health problems to bad water conditions. If your fish begin to look sick, test the water. Anything more than ‘0’ in readings of ammonia or nitrite is unacceptable. 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. This is not always effective for a number of reasons.

Firstly, plants and bogwood soak up medications, diluting the dose. Efficient biological filters can also help to break 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 large 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. You will need to get it diagnosed and treated within a day of discovering 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. Get a good book, with pictures, that will help you investigate the causes.

32. Proper use of medications

Using medications is not something that we should take lightly. Most medications are made from dangerous, sometimes carcinogenic, chemicals. They should not come into contact with our skin if we can help it. Use 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. Censure you check the use by dates and write the date you opened them on the bottle. 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. 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. Mixing them with other species in your community tank straightaway may mean them introducing or catching a disease. 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. While pond fish are naturally more prone to disease at certain times of year.

Don’t treat prophylactically too often. Parasites can gain greater resistance meaning they may not be cured by 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. You can even dig around and find their actual food and have a go at catching some fish yourself. You will discover so much in a short time and be able to provide a lot more for your chosen fish when you get back. You may even get a good sun tan, too!

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

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. 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 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. The water will seek to pull minerals and salts from other media like gravel, and 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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