Getting started in fishkeeping can seem like a minefield. There's a lot of conflicting advice that leaves the prospective keeper confused and unsure who or what to believe. So here's a guide to get it right. Hardware The Tank: Get the biggest tank you can afford and have space for. That little 35ltr tank might sound like it's the perfect size for the beginner, indeed, they're often marketed as such by the manufacturer, but the smaller the water volume, the quicker water quality and chemistry can fluctuate, giving you less time to notice something's wrong. It may sound backwards, but bigger tanks are easier to get right. Toxins such as ammonia, nitrite and nitrate tank longer to accumulate, and changes in temperature and water chemistry are slower, maximising the fishkeeper's chance to notice something's wrong and take action. A standard 20gal/90ltr will make a good starter tank. Large enough for water chemistry to be fairly stable, but small enough that it won't daunt you. Rectangular long tanks are best as they have the biggest surface area for gaseous exchange (oxygen in, CO2 out). Avoid bowls for that exact reason -, to maximize surface area, the bowl would have to be half full at most. The Filter The filter is the single most important piece of equipment in the tank. It is literally the life support system of the fish and inverts. Without the filter, the fish are swimming in their own excrement. It's that simple. There are four main types - internal, external, HOB and sponge filters. Internal Filters - Ideal for tanks up to about 120ltrs or so. They're designed to be fully submerged in the tank. Pros:. Space saving and no chance of leaking. Cons: Overly powerful filters can pull the fish towards it, causing it to struggle against the current. External Filters - Ideal for tanks over 180ltrs. Canister or external filters sit underneath or beside the tank and connect to the tank by hoses for the intake and outflow. Pros:. Maximises tank space by taking the body of the filter out of the tank, they are usually bigger than other types. Bigger means more space for more media. Quiet, and easily customizable. Cons:. Tend to be more expensive than other types, can be awkward or more labour intensive to clean. HOB (Hang On Back) Filters -. These are sort of in between the internal and external. The impeller pulls water up out of the tank and forces it through the filter media and back into the tank. Pros: Easy to use, set up and clean. Relatively cheap, and good for beginners. Good for small to medium tanks Cons:. Not as easy as the other types to customise. Can be noisy, limited space for media, few options in terms of spreading the input and output, potentially leading to dead spots in the tank. Sponge Filters - Ideal for Betta fish, or for nursery tanks, sponge filters consist of a tube surrounded by (surprise, surprise) sponge or sponges. They are the only filters that do not run on their own power and require an air pump and air line to work. They're the cheapest type of filter on the market. Pros: Cheapest types of filters on the market, super easy to set up, Easy to clean, and perfect for fry or fish such as Betta Splendens which have long, flowing fins with a tendency to get caught. Reliable. Effective at biological filtration. Cons: Not self-powered, and therefore depending on air pumps, which have a tendency to be noisy, so not good for tanks in bedrooms. They're not exactly pretty to look at either, although they can be hidden by decor and plants. Heaters Heaters are essential in temperate or tropical tanks. Most are internal, although you can get integrated filter-heater sets and inline heaters designed to connect to the return hose on canister filters. The higher the wattage, the more powerful the heater and the quicker the water warms up. However. The caveat here is, that if the thermostat breaks down and sticks on, it can fry the fish. For tropical tanks, look for a heater with no less than 1 watt per gallon. Slightly bigger is fine. For temperate fish, a heater rated for tanks slightly smaller than your may suffice. A 50w heater in a 75ltr tank could be all you need, as the emphasis is more towards stopping the temps from getting too low. Hoods Many tanks (although by no means all) come with hoods as standard, especially if you get a starter or all-in-one kit. They often have lights installed too. Whether they come with the tank (and lights) or not, aim for one that fits snugly, especially if you intend to keep fish that are known for jumping. Lights Lights are much more important to plants than to fish, although it gives them a sense of "day" and "night". Traditional lights are the T8 or T5 fluorescent light strips, available online or in pretty much any LFS (Local Fish Store), but nowadays LEDs are becoming more and more popular. The strength of the light will determine the type of live plants you can keep. Many fish prefer dimmer lights, so if you wish to have plants that require bright light, make sure you also provide floating plants for the fish to find shade. Accessories Testing Kit Second only to the filter in terms of importance, a master kit allows you to check parameters the second you notice something's wrong. Liquid kits, such as the one in the image, are often more accurate than the test strips. A lot of people take a water sample down to the pet shop or LFS for testing, especially when they've first set up their tank. The problem with that is, LFS usually have a tendency to say "it's fine" or "it's a little high", or some other vague description which tells you and us absolutely nothing. Fine for whom? You? Them? The fish? The other problem with relying on the LFS is more obvious. Let's say you got your water tested in June, and "all is fine". Then, at 5pm Sunday evening in the beginning of August, you notice a fish or two clamping their fins at the bottom of the tank, gasping. What's going on? Is it ammonia poisoning? A pH crash? Haemorrhagic septicaemia? Gill flukes? You don't know, I don't know. The man in the moon doesn't know. And you can't rush out to the LFS and get the water retested because it's shut. All we can advise is that you carry out an emergency water change of 50% and buy your own kit first thing in the morning. But if, at some point in July, for example, you went ahead and got your own kit, you could reach for it the second you notice something was wrong, test the water yourself and realise there's an ammonia spike. Bingo! 50% water change and retest in the morning. Dechlorinator Another essential item. There are plenty on the market, some more concentrated than others. Dechlorinators remove chlorine and chloramine from tap water and detoxify heavy metals. Some, such as Seachem Prime, also detoxify ammonia and nitrite temporarily, keeping them away from the fish while still allowing the filter to do its job. Background The background is a little more controversial than others. Some say they're unnecessary, others, such as myself, believe they are. Fish are pretty far down the food chain. They have a lot of predarors., Including the resident cat. Being viewable on all sides can make them feel skittish, and limits the places they have to hide to the middle of the tank. A background can be as simple as painting the outside of the back panel, or as complex as a 3D internal background that needs to be glued with aquarium-safe resin to the back of the tank. It's up to you and how much you want to spend. If you go for paint, or a plain background like I have on my big tank, go for darker colours - they help the colours of the fish and decor stand out more. Substrate Gravel, sand or planting substrate. Substrate is another thing that helps the fish feel secure. Substrate becomes more important if you choose to have bottom dwelling fish such as corydoras catfish or loaches that sift through or bury themselves in it. In that case, sand is best. Play sand is usually fine - but, to be certain that it's inert, run a water chemistry test on it before you do anything else - you want to know if it alters pH, GH and KH before it goes in the tank. Not after. Gravel Vacuum or syphon Bit of a misnomer here because it cleans sand just as easily as it does gravel. This is another essential piece of equipment as it removes detritus and leftover food that gets stuck in the substrate, which can lead to ammonia spikes. Decor OK, this is the fun bit. This is where you can really customise your tank and make it your own. There are three important things to remember with decor. 1). The more places the fish have to hide, the more secure they'll feel and the happier they'll be to come out into the open, which means you'll see them more. 2) Resin ornaments can have sharp edges, so run your finger over it, paying particular attention to any hidey holes designed for the fish to swim through. You can sometimes sand these down and rinse the ornament thoroughly before you add it to the tank, but check again first. 3). Avoid plastic plants if you're intending to keep longfinned fish such as Bettas or guppies. Some natural ornaments, such as driftwood, almond leaves, alder cones etc leach tannins into the water which can help reduce pH and give a natural look to a blackwater setup. Some fish might prefer that look: This is my own 200ltr tank set up with tannin-stained water. But if you want that battleship graveyard with skulls and anchors and a treasure chest, or want to replicate the seabed inside the Bermuda Triangle, go for it. Who am I to stop you? Just add some plants and maybe a couple pieces of redwood for a touch of authenticity.