My Aquarium

I have a new(ish) toy which is now an established fish tank. I chose tropical freshwater fish because it is easier to maintain and requires less equipment to work. Plus, the fish themselves are cheaper, averaging a few pounds per fish as c.f. hundreds of pounds for tropical saltwater fish. The other type of fish you could choose would be non-tropical cold water fish such as goldfish but I wanted more than simply one species to look at. Once you've decided what type of fish you want, you can move on to the equipment needed.

 

The Equipment

First you need to decide on the size of the tank. The best way to do this is to decide on which room to place the tank (living room is the best because you'll see it the most there) and then decide what size you want and where it should go. It shouldn't dominate the room and remember that you need access in order to maintain and clean it regularly. Also, the bigger the tank, the bigger the filter system and the possibility that you will need a big air pump to go with it - all of which contribute to background noise it will give out. I decided to get an "all in one" package that included the tank, lights, filter, heater and cabinet to put it on.
Tank: This can either be made of acrylic or glass. Acrylic can be moulded into non-flat shapes (e.g. curved tanks) and can be optically more perfect, but they will scratch very easily when being cleaned, something that won't happen with glass sides. Glass, however, is much heavier (therefore difficult to manoeuvre if you want access for maintenance to the side closest to the wall).
Cabinet: My setup came with a handmade Oak cabinet making it blend in with my existing living room furniture really well.
Lights: Most cheap lighting is CCFL (fluorescent tube type), but the better option is LED lighting which gives a more neutral spectrum and even spread of light without the noise and power consumption that flourescent tubes give. Plus, they will last much longer than CCFL will. I have pure white for day time viewing and pure blue for moonlight simulation (night time viewing). I have them separately connected to timer plugs allowing the main lights to auto-switch off at night whilst the moonlight blue LEDs switch on for an hour before all go off. The best lights are the ones found in the fish shops used to display the fish and use ultra bright RGB LED lights (usually with their own fan cooling) but these are extremely expensive.
Filter: Generally speaking, you need a filter that can process the whole volume of the tank about 4 times per hour. In reality, a lot of volume will will be taken up by gravel and ornaments so the actual water volume is smaller so by calculating this way you end up with a slightly overspec'd (a good thing) filter. So for instance, a 200l tank needs a minimum 800lph filter. The best filters are external filters that use tubing to pull in water from the tank and also to return it. These external filters are generally much more robust and powerful than the smaller ones you buy that sit inside the tank, plus they take up no aquarium space and lend to a cleaner overall look. However, bare in mind that when the seals eventually go (they last about 1½-2 years on average) and need replacing, the filter will end up leaking all over the floor. This might be the first sign that you need new seals so beware if you have an MDF/chipboard cabinet which will buckle and break when soaking. The seals to look out for are the seal that sits between the head/motor unit and the canister itself (the main seal) and the seals that sit in the 'flow-stop' plugs that connect the main hoses to the unit (sometimes these are irreplaceable and you need to buy a complete plug module instead but they are fairly cheap).
Steriliser: Filters inactivate the inorganic & organic toxins in the water (carbon inside) plus they convert waste ammonia to nitrites and then nitrates (bacteria inside). However, the microscopic algae, harmful bacteria, diatoms etc etc in the water will continue to circulate and build up. This is why you can occasionally get algae blooms and bacterial blooms. A UV-C light, with enough power, when shone through the water will kill these organisms. The UV-C sterilisers are normally placed after the filter so that it shines through cleaner water and has better penetration.
Heater: Heaters are designed to keep the water at a constant temperature and are usually placed within the tank where there is highest flow (to disperse the heat more evenly throughout). It's also worth noting that regardless of what the manual states, they always work better at a 45° tilt. I have mine set to about 25℃ for freshwater tropical.
CO₂ System: If you have a planted tank, this is a must in order to ensure the correct 30ppm of dissolved CO₂ that will allow your plants to thrive (and still be safe for fish). You could simply buy a kit with 88g CO₂ canisters but these are expensive to buy and replace every 3 weeks (I calculated cost over 3 years to be 4x higher than buying a full system in the first place, if using 1bps over 12hrs). You could even go cheaper and use a DIY system but these can be messy and tiresome to set up. The best systems consists of a dual stage DIN regulator (not simply a single stage that has 2 dials) that will not only tell you the cylinder pressure but with which you can also adjust the pipeline pressure to the diffuser. There is also a 3^rd dial that will allow you to adjust the bubbles per second. The reason for a DIN screw type is to allow 2kg CO₂ Fire Extinguisher cylinders to be used which should last just over a year. They also can come with a solenoid to allow auto-on/off times if used with a timer plug (I have mine set to go on/off about 1hr before the lights do). You can finally buy all-in-one "check valve/bubble counter/ceramic diffusers" and you'll need a drop counter to tell you when you're at the right [CO₂] level (blue if under, green if OK, yellow if over).

Setting It Up

Now, you'll need to decide what to put in besides the fish. I made an active choice to make the habitat look as natural as possible. This meant no gaudy multicoloured sand or gravel and no weird and wonderful ornaments too. It also meant that because I wished to recreate the fishes normal environment as much as possible, I would opt for natural brown gravel and cream sand. However, as I wanted real life plants (no plastic rubbish) they would need their own nutrient gravel to go in first, so I lined the bottom of the tank with about 1-2" of substrate. This gives a soil-like structure through which your plant's roots can anchor and flourish in - without it they won't live. It can be any type or colour you want because you won't be able to see it (you cover this layer up completely with the gravel or sand of your choice). Plants have an added bonus function of absorbing CO₂ and releasing O₂ into the water, meaning you have no need of an air bubbler if you have plenty of plants.
Now, to allow efficient recycling of waste products, bacteria need to establish to convert these into harmless byproducts. The bacteria will end up predominantly residing in your gravel/sand and your filter. If you use very tightly packed sand, it will promote pockets of anaerobic growth which is unwanted. You need aerobic nitrifying bacteria instead, so larger grained gravel will be better in the long run for your tank. I chose a medium grain dark brown gravel for most of my tank to simulate the bottom of a tropical river bed (the fishes natural habitat). I then added a splash of sand to contrast the colour a bit. Before adding the gravel or sand, place it in a bucket and cover with boiling water to sterilise it. Once done, wash it thoroughly through to rinse out any fine cloudy particles and detritus. This is then finally added above the substrate.
Next, choose your ornaments. For the natural look, I have a piece of bogwood which will release tanins into the water to keep a correct pH as well as act as a mild anti-bacterial agent too. My one artificial ornament is a log look-alike which acts as a hiding place for the more shy fish. Apart from that it's only plants.
My plants were simply a random selection of 12 from my local shop and over the past 8 months have grown well to transform the tank into a natural looking environment. As well as helping with oxygenation, they provide plenty of extra hiding places for the fish and they additionally use the waste nitrates as food thus reducing toxic levels.
The most important step is up next...after assembling the wood/ornaments as wanted and landscaping plants, slowly fill the tank with water, treat with a dechlorinator, add a pinch or two of fish food and leave it alone and running for about a month. I know it's tempting to immediately buy fish but you absolutely need the bacterial colonies to establish within the tank first, otherwise you'll end up with dead fish. The fish food provides the initial nitrogenous compound that will hopefully kick start the nitrogen cycle.

The Fish

After a month, it's time for the fish.

I have picked only peaceful fish which will coexist with each other. Even though this does restrict my choice somewhat, it results in a healthy thriving population with little to no stress and death and I still have plenty of species to choose from. These range from gourami's (dwarf and pearl) to various guppies, platys, tetras (cardinal and neon), danios (zebra and leopard) and rasboras. Some fish serve specific functions (like my otocinclus' which clean algae from the glass or my corry's that clean the gravel for me) whereas others are just eye candy (like my siamese betta).

Feeding & Maintenance

In setups with working CO₂-O₂ and NH₃-NO₂^--NO₃^- cycles, feeding the fish is the only daily maintenance that is needed but it is also the point at which most fish can die! The problem is that feeding the fish is your main interaction with them, so naturally most folk feed them a lot. However, not only is a fishes stomach only about as big as it's eye, but they're cold blooded. This all means that they don't need much to eat but invariably they end up getting fed too much if you're not careful which ultimately contributes to a large ammonia load, clogs the filter and kills the fish. As an example of the correct amount, I have about 40 small fish in a 50 gallon tank and they are fed 6 times a week (e.g. nominate 1 day not to feed them). The daily feed is only ¼ of a level teaspoon of fish food which they can consume completely in less than five minutes.
It also requires only a ¼ water change once a month (don't change too much or you'll shock the fish) and a filter clean once every three months (not too judiciously as you'll kill off the bacteria you spent months growing in there). Apart from this, the rest is just enjoying the view (here is someone else's setup, very similar to mine):

You can landscape yours in any way you want as well and it will end up looking great whilst being a good stress reliever after a hard day's work.