Pet shop Gloucester advice on basic fish care

Pet shop Gloucester advice series on basic fish care. We get a lot of customers asking us for the basics on how to look after fish and an equal amount asking about how to resolve problems with their tanks. The response is normally the same for both enquiries so we have put together a basic guide, with a few does, don’ts and optional bits.

This a basic, generic guide. It is not intended to tell you the exact quality parameters, tank size, best food, breeding requirements etc. of your prized Malawi cichlid or red bellied piranha. Also it does not touch on marine tanks (other than basic principles common to all tanks). It is intended to help those new to fish keeping to help keep the tank looking presentable and the fish healthy. For more detailed information on individual fish types, breeding etc. we recommend you buy a good book or come in speak to us so we can point you in the right direction.

  • Selecting the tank. We get asked “do you have any goldfish bowls” quite a lot. Especially after the Newent onion fayre. Kids win a goldfish on a stall and then the parents realise they have nothing to put it in. We don’t sell them. The smallest tank we sell for fish is 25l, complete with a filter. Smaller than this and without a filter is stressful to the fish and a lot more work for you. Don’t bother, get a proper tank and filter. If you don’t want to be lumbered with an unwanted goldfish won at a fair, show some parenting skills and don’t allow your kids to go on the stall. This practice of giving fish as prizes is cruel in our opinion. Decide up front how many fish you want and what type of fish (tropical or cold water). Remember the fish will grow so find out how big and how many you could have in what size tank. Despite what people will tell you there is no hard and fast rule. However, a reasonable rough guide is inches of fish to length of tank surface in inches x depth of tank in feet(for normal shaped tanks). So a 2′ x 1′ tank is 24 inches of fish (say, 4 goldfish). This is a rough guide, it depends on the fish, filtration type etc. but it gives you a starting point.
  • Once you have decided what type of fish and what size tank you want, think about the equipment. The basics you will have to have for cold water are a filter and lights (if you want to see the fish. For tropical you will need an appropriately sized heater as well. The filter should be sized to suit the tank you have bought or are going to buy. If you buy a set up deal then the filter should be sized appropriately. If you get a filter that is too small you will not be able to maintain a clean tank. If you get one that is too large your fish will be constantly trying to fight the whirlpool you have set up in your tank. Obvious really but it also depend on what fish (or other animal) you are going to put in your tank. For example piranha need a larger filter than other fish as they eat high protein food (meat) and also make a lot of mess whilst eating it. On the other hand an axolotl (I know it’s not a fish but it goes in a fish tank) does not like any current so you will either need a smaller filter with the outlet turned against the glass to still the flow or a variable outlet filter that you can turn down. Better still you could use an under gravel filter. I am not covering them here as they are simpler to manage than cartridge (internal or external). Basically if you clean the gravel when you change the water you have cleaned the filter. Most normal tropical and cold water fish however will do well with the normally sized filte/ tank combo. Filters can be internal or external. Internal are fine but do take up room in your tank. External can be bigger without taking up any extra room. If getting tropical fish the heater also needs to be sized for the tank. Too small and you will not always be able to lift the temperature of the water enough (i.e. if it is cooler in your room). Too big and you will get large peaks and troughs in temperature as the heater switches on and off and possibly localised hot spots, not good. If you are having tropical fish it is essential you have an independent thermometer as well. The thermostats on the heaters are notoriously inaccurate and should only be used as a starting guide and they do fail occasionally. You need to be able to see what the temperature actually is and monitor it at least daily. Lighting is optional really if you don’t have real plants but you are not going to be able to see much without it. There are a lot of different lighting set ups and tubes etc. each suited to different situations, bringing out the colour of the fish, encouraging plant growth etc. It’s too varied to go into here but most modern tanks come with a lighting system of some sort. Make sure, if you want to be able to grow plants or have highly coloured fish that you can fit the necessary lamps.
  • Gravel and decor. I suppose gravel or sand is optional but I wouldn’t recommend doing without. We are starting to get into the detail of the tank set up here, which I want to deal with next but you need certain bacteria in your tank and they live in the gravel and in the filter. It looks nasty anyway, having food waste and fish excrement on the base or a tank with no gravel or sand. Which you decide to have depends on what you are putting in the tank. Some fish need sand to burrow in or feed off of. Also if you are intending to have plants there are a number of specialist substrates that can encourage root growth. For most tropical and cold water fish gravel will suffice. What colour is up to you. I like natural colours but I have a customer who likes fluorescent pink. Each to there own, they all perform the same function. You will need to decide if you want real plants or fake, or any at all. Tanks with just flat rocks built in stacks can look fantastic. Again it can depend on which fish you want. Don’t put silver dollars (a vegetarian relative of the piranha) in a well planted tank because it won’t be well planted for long! Some of the newer silk plants look very effective. Personally I have always preferred a planted tank. If you want real plants you will need to provide then with additional nutrients and  you may want to think about some form of CO2 system to encourage growth (and as we have already said there are specialist lighting tubes that help too). In the end it is up to you and most normally stocked fish will do well in either (unless you want to breed and then you may have to have real plants of a certain type)
  • So you have decided how much room you have and  so what size tank you want. You have decided what fish you want to keep and you have bought an appropriate tank. Now you want to set it up. First, decide where it is going to go (see our previous blog “Location, location location”), set up the stand if you have one and make sure you follow the instructions on placing the tank. On older tanks the bottom glass just sits on the surface underneath. If this is the case you need to place a layer of polystyrene or other suitable material in between. If you don’t just a small piece of grit trapped between the stand surface and the glass can put stress on the glass when the tank is filled and crack it. One ruined tank, flooded carpet, insurance claim and increased premium – nice. More modern tanks generally have a plastic frame or feet on the bottom creating a small gap, making this unnecessary. Follow the instructions that come with the tank, it’s important.
  • Now the tank is sited and built up, add the gravel. Wash it first. Some are better than others but if you don’t wash it thoroughly it can take weeks for your tank to clear. Go over the top. It may take you half an hour but it could save you weeks of torment. If you have decided to plant your tank and use a special substrate put this in first, before you top it with gravel. Now you are ready to add water.
  • Before you add the water you need to understand a couple of things. Firstly, the easiest to deal with, chlorine. Chlorine is added to drinking water to make it safe to drink. It kills bacteria (and other organisms) by breaking down their membranes. It does the same to a fishes gill membranes and will kill the fish. Levels in tap water are a lot lower nowadays but it is still there. Leaving the water in a bucket overnight will dissipate most of the chlorine but will not effect the chloramines (chlorine combined with other molecules). These stay around for many days, that is what they are there to do. You will need to add some chemical to neutralize this chlorine and the chloramines. We sell King British Safeguard but there are other brands. They all do the same thing. Follow the instructions on the bottle. It is also a good idea at this point to add another product. We sell King British Safe Water. This is basically the good bacteria you will need to break down the fish waste, in a bottle. The other thing to consider is pH. If you are going for specialist fish that require a very tight pH range you will need to treat the water accordingly. pH is a measure of the hydrogen ion content of the water. The pH scale is logarithmic. That means that a small change in pH is a massive change in hydrogen ion content and a big deal for some fish. Fortunately most fish sold nowadays are farm bred and are much more tolerant of a wider range of pH. What this means is that you wouldn’t normally have to worry about pH in a new tank. Tap water pH is well buffered (certainly in the Severn Trent region) to around 7.4 to 7.6. For most farm bred fish this is OK. If you wish you can easily buffer this down by adding the appropriate amount of pH buffer which you can buy from us but unless you are thinking of breeding the less tolerant fish you probably don’t need to bother. Some people use rainwater in their tanks. The pH of rainwater is much lower and can be down to pH 5 in this country. In this case you would need to buffer up for most fish as that is quite acidic. A pH of 7 is neutral (not acidic or basic) and is fine for most fish.
  • Right. Your tanks is set up and full of water. Switch it on and marvel at your creative skill but DO NOT put any fish in it yet. It is essential that you let the tank “mature” a bit first. A week is an acceptable amount of time to wait before putting in fish. Essentially what you are doing is allowing the bacterial waste disposal system to grow. Fish eat food, they use this food to provide them with energy and grow and this process produces waste. When we eat protein we produce nitrogenous waste that we dispose of by going for a wee. It leaves our bodies and goes elsewhere. A fish’s nitrogenous waste goes into the water that it is swimming in. It takes the form of ammonia (this is why fish smell fishy – that’s the ammonia). Unfortunately ammonia is highly toxic to fish. How then have fish survived for millions of years? It’s becasue they either live in rivers which have currents that carry the ammonia away or in large bodies of water (lakes and the sea) which again have currents and that dilute the ammoina until bacteria can break it down. Your fish are contained in a fixed volume of water. There is nowhere for the ammonia to go. This places certain constraints on your tanks system and this is where most problems with fish keeping orignate.
  • Ammonia is broken down by two types of bacteria, firstly into nitrite (less toxic but still dangerous to fish) and then to nitrate, far less toxic but it will gradually build back up to toxic levels as there is nowhere else for this to go (more on that in a bit). In your tanks these bacteria will live in the water, in the gravel and importantly, in the filter. The water is pumped through the filter over a sponge or ceramic matrix where the bacteria feed off the ammonia and nitrite converting it in the process to nitrate. If you add fish before these are there in sufficient numbers they are overwhelmed and ammonia rapidly builds up to toxic levels. This alone can kill fish but more likely it will make them stressed, allowing disease organisms in, which will then kill the fish.
  • So your tank is now mature and you are going to add fish. Before you do, make sure that your filter outlet is near the surface of the water facing across the tank surface (unless you have an axolotl!). What you want is for the surface of the tank to be rippling as much as possible. This encourages the transfer of oxygen and carbon dioxide between the tank’s water and the air.In essence it allows the water to breath and not go stagnant. Very important.
  • Adding fish. It is important that you only add fish a few at a time into a new tank. The bacterial colonies will be there but they haven’t had any food (fish waste) so they will not be fully functioning. By adding a couple of fish at a time you allow the colonies to grow with the number of fish. I know it’s annoying but there is nothing worse than going out and buying a load of fish and them all dying. You will blame the shop but it won’t be their fault. Slowly, slowly catchy monkey. When you add fish to any tank, place the bag with the fish in into the water and leave it alone for 10 or 15 minutes. Then net the fish out and place them in the tank. Don’t just get them home and tip them in. This will almost certainly temperature shock them and either kill them straight away, or lower their defenses letting diseases in. Fish are protected by a slime coat. You want this to stay intact, it works a bit like skin in that it keeps out the nasties. Oh and don’t put the water in the bag into your tank. Assuming the water doesn’t contain any diseases (and thats a big assumption) it will contain all the waste from the fish. Get rid of it and not into your new tank.
  • Your tank is up and running, some fish are in and looking good, you had better think about feeding them. I can’t go into all the different foods on the market for different types of fish here, it would take too long. Just ask when you get your fish. Be careful though, often you will be recommended to only ever use a certain food. This is normally because that is the food they stock, so of course it’s the best. It  may not have anything to do with what is best for the fish but what is best for the shop. Actually, most modern foods are OK depending on the type of fish; some do need specific foods. I would recommend you don’t stick to one thing (just flake for instance) but vary it with dried stuff and frozen stuff. You can use live but you are risking introducing something nasty or poisoning the fish with toxins from food that has died in the bag. Importantly you do not want to overfeed. It is the commonest reason for excessive algal growth. Put in enough to be gone within a minute (roughly). If it is still floating about on the top on lying in piles on the bottom after a couple of minutes, get it out and feed less next time. Once or twice a day is enough. We only feed once a day.
  • Now all you have to do is sit back and admire your tank and fish. Oh, apart from the maintenance of course. You will have to get into a routine of partial water changes and tank and filter cleaning. Firstly water changes. We have already learned that ammonia is converted into nitrate. This is plant food so your plants will use some of it to grow but not all. Of course you may not have any real plants. So you are now feeding algae, which will grow and quickly become unsightly. Left alone nitrate could build up to toxic levels. So every two weeks, take out some of the water (normally around 20-25%) and replace it with fresh (treated of course). Clean the glass with an appropriate cleaning pad first so that removed algae is taken out with the water. Either use a gravel cleaner to clean the gravel as you empty the water or stir the gravel with your hand before emptying the water. Both methods result in the removal of solids from the gravel with the water. Left in the tank these solids would start to rot and release toxic compounds, not good. If you have tropical fish and you just replace 25% of your nice warm water at 25 degrees Celsius with winter tap water at 5 degrees Celsius, guess what, you will kill some fish, so add it gradually. I use a bucket on top of my tank with a small bore pipe syphoning it into the tank over about 15 minutes but you can use your own method. If you want to warm the water that’s fine but I wouldn’t use water from the hot tap, it can contain copper (from your storage tank). If you have a combi boiler that provides instant hot water it’s probably not a problem.
  • Every second time you do a partial water change, clean the filter. All filters are slightly different so I’ll be generic and you fit yours in where appropriate. If there is a poly prefilter (white fluffy pad), dispose of it and replace. It’s just there to take out the big bits to stop them clogging the filter elements. You could be tight and try cleaning it but it rarely produces good results and they are only cheap anyway. Remove the sponge and rinse it out in the dirty water you have just taken out, NOT UNDER THE TAP. Rinsing under the tap kills all your nice friendly waste disposal bacteria. If you have carbon sponge (black) this will need to be replaced every few months. Carbon adsorbs (that’s adsorbs, not absorbs, they are different) organic molecules onto its surface and has a finite number of adsorption sites and so gets exhausted. Similarly if you have a nitrate removal sponge (usually green) this too becomes exhausted and will actually start releasing nitrate into your water so will need replacing every month. Otherwise you don’t need to replace the filter elements unless they start to physically deteriorate (from all that wringing out). Clean what needs cleaning, replace what needs replacing, put it all back together, job done. Depending on how many fish you have you may have to increase the frequency of water changes and filter cleans. One important thing to point out. Do not allow any heaters to become exposed to the air, they should always be submerged when on. If you have to expose it, switch it off first. they can overheat as the thermostat only works under water and have been known to catch fire (if mounted in a plastic cage).
  • Assuming you stick to your regime and get your fish from a good supplier you should be OK. However there are a few things worth mentioning before we briefly cover diseases. First siting the tank. I’ll mention it again although it has been covered in “Location, location, location”. Don’t have the tank in a busy walkway or next to a slamming door, it will stress the fish. Don’t have the tank in direct sunlight and don’t have the light on for more that 10 hours, both will cause excessive algae growth. Do check the temperature every time you look at the tank. If the thermostat goes you could boil the fish, if the heater goes the temperature will drop and the fish will start to suffer diseases (not necessary for cold water fish of course – no heater). Remember warm water contains less oxygen than cold water so a few degrees rise can make a big difference. Don’t use aerosols around the tank. Many contain chemicals that are highly toxic to fish. Too much deodorant has killed people so it can certainly kill fish.
  • Diseases. This is a subject that has had many very weighty volumes written about it so we cannot cover it here but we can give you a quick run through of what you are most likely to encounter in very general terms. Diseases can be split into five main categories, internal parasites, external parasites, bacterial infection, fungal infection and viruses. Internal parasites are virtually impossible for the average fish keeper to spot and diagnose. They are single or multi-cellular animals that live inside the fish and so are usually invisible to us. Often the first time you know there is a problem is on the death or near death of the fish. External parasites live on the outside of the fish and so are often visible. Those such as fish lice and anchor worms are quite obvious and easy to treat with propriety treatments. Bacterial infection can be internal or external. Even internal infections can be spotted with swelling (dropsy), misshapen parts of the body etc. External signs can be fin rot, ulcers, bloody fins, etc. Fungal infections can be the primary disease but are more frequently secondary to another sort of infection (as are, often, bacterial infections secondary to injuries or external parasites). Viruses are difficult to diagnose and are often confused with internal bacterial infection. They are also difficult and in some case impossible, to treat. The best thing to do if your fish are showing signs of disease is to take sample of the tank water along to have it tested and note as many symptoms as possible.You can then be advised on what is the best treatment to try and other considerations to take into account when giving medication (like removing carbon filters or invertebrates). Don’t be offended if it is pointed out that there is a problem with the tank water. Most diseases only manage to take hold if the fish is stressed from poor water quality. I want to say more but I am getting into the realms of a treatise on fish diseases, which is not what this blog is about. If you wish for more advice come in and see us and we would be glad to help.

So there are the basics which should keep your tank healthy. This subject is huge, as big as the variety of fish available. Fish commonly found in aquatics shops come from all over the world. Each country will have a wide range of habitats from upland streams in the Andes through farmland into the Amazon rainforest and literally out into the forest itself when it floods, through the brackish estuary into the sea. That’s and awful range of parameters for you to contend with. Pick fish from a similar environment for each tank and you should be OK. As we have said most fish are now farm bred and have become more tolerant of a wider range of conditions. If you really want to keep fish, get a good book and read up a bit, it always pays dividends.

See you soon.


The Angell Pets team




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