What are the three top things about setting up an aquarium that I should know

What are the three top things that I should know about setting up an aquarium ?

CA members answer this question based upon years of know-how and empirical trial and error. Benefit from their experience and read on !

OK, CA members, what do YOU think are the three essential things to know about setting up an aquarium !

1. understanding about ammonia and nitrates and how to cycle the aquarium properly.

2. Understanding why and how to do a water change

3. Knowing the needs of a fish before you buy it. Not all fish are the same.

So there is a lot more to fishkeeping than that, but you said the top 3.  

I agree with Starfish on those important points, but I'll add what I think are some others.

1) Understanding that whatever fish you buy - it is not the size of the fish in the store that matters, but what it can become. Never buy any fish without researching it from 2 or 3 sources, even if that means going home and leaving it behind. One inch per gallon is a formula for failure (or increased fish sales by stores...). One inch goes up, down, sideways, diagonally... Large fish in small tanks kill the fun of this hobby;

2) Be prepared to change water - the tank will never run itself;

3)Location matters. In a perfect world, the tank is in a quiet, easily (and often) viewed place close to a sink and to an electrical outlet. It isn't in direct sunlight (algae....) but the room can be bright. The floor isn't bouncy, and the tank is even. Once you fill a tank, it has to be drained to be moved. That's not an awful job, but with a little thinking in advance, the tank can settle into a nice spot and provide years of calming enjoyment.

3.5) Oh yeah, I'll cheat in a fourth - hang around this forum and contribute what you learn as you go along. Fishtanks are fun to talk about, and what is often a solitary hobby in your house can become a social hobby online or in a local aquarium club. Knowledge gained is to be shared!

I think several of these points are important, but I will put my twist on it....

1) Why do I want to have a tank....? I have seen many different reasons for people wanting to buy a tank and set it up... For some it is going to be a relaxing hobby (what little they know). For others it is an educational thing either for themselves or children. I have also seen some make a snap decision because they want to keep a piranha or some predatory fish to watch it eat live goldfish because they think it would be cool. Some thought has to be put into the responsibility of setting up a tank.

2) Do you have the patience to set up and keep a tank...? Too many people see a fish or an aquarium and decide that's what they want. Movies like "Finding Nemo" don't help when someone thinks they can go out and buy a little glass box and throw in a fish right away. We live in a world of instant gratification but this does not work in the aquarium scene. People need to understand that things take time to set up and develop and they may have to sit on their hands. This can be especially true of a marine set up but it holds true of all aquariums.... Take the time to allow success.....

3) Do you have the information you need to start an aquarium....? There is a lot of information out there these days and it is easy to access many answers to so many questions.... But are you asking the right questions to start out....? Can you trust the information that you are getting....? Is the store looking to make a quick buck or do they care and want your business....? Do the people you are asking the questions of have the correct answers....? There are many ways of running a tank and so many different parameters that encompass setting up an aquarium. Geography plays a part (don't try to raise discus in an area where your water is liquid cement, for example) as does the amount of money you can spend (it's not realistic to think a 100 gallon marine reef set up if you can't buy the proper equipment for the long run). Look for answers to the same questions from several sources and trust the answers that you get back that sound the same... if you get too many discrepancies, do some more research. Also, find out how much time you will need to spend on the tank... Who will be feeding it....? or cleaning it.....? What kind of fish do you really want and how big of a tank do you really need....? If you take the time to understand these things before you set up your tank you will have a much better chance of having success with that tank.... you will stay in the hobby a lot longer...... and the animals in your care will have a much better life......

1.  Nitrogen Cycle - So many newcomers are lost from the hobby for a lack of understanding of the need to properly cycle an aquarium - whether it be fish in, fishless, seeded etc.  

2.  Understanding Fish Needs - Selecting a stocking level appropriate for the size of tank, selecting compatible species and stocking them in appropriate numbers to avoid them becoming stressed.

3. Water Changes - The importance of fresh water for aquarium fish.  Remember, in nature they have 100% water changes every day.

Looking back at my first tank, understanding these above three points would have made a world of difference and saved a lot of frustration. A buddy and I started at the same time and had the same experiences. Bad advice advice and a lack of knowledge led to both of us losing quite a few fish. I had stocked one of every kind of tetra under the sun, some mollies and a common pleco in a 10 gallon (huge no no) and he had fancy goldfish, a few tetras and a common pleco in a 20 gallon(clearly a recipe for disaster). He left the hobby and I pursued more information and better methods. On the bright side, I inherited his 20 gallon tank! Since developing an understanding of the above three concepts, I have had great success in the hobby.

1. Nitrogen Cycle,

2. Patience,

3. Research. Never trust what companies try to sell us. This hobby is for people who like to go outside of what's sold to us and for us to look for the better alternatives.

I agree with ALL of the above, but to me the top thing should be to respect the lives of the fish you take on in your tank.  
With no regard to that you cannot possibly succeed at keeping fish.  If they are just considered replaceable you will never provide the care they need to survive, much less to thrive.
Yes, you will have some losses but if you grieve over those losses you will learn from those mistakes and go one to be a better fish keeper.
If they are "just fish", you will never care enough to become a true, devoted aquarist and your fish will always suffer.

All the above is good advice and very true Nyleveiams is some of the best after research were you will find out about the nitrogen cycle, fish species needs and tank size,water needs(soft ,hard, temperature) required to take care of the fish you have in your care or will have.
We have all had bad experiences due to ignorance,bad luck etc.
We just hope our advice will ease some of the bad experiences and help make it more fun and enjoyable ( and maybe save a few fish lives as well.)

Thank for resurrecting this thread @Fores41

I think it is great to look at what we should know about the hobby and different people will take a different perspective based upon what they want to get out of the tank. I started to think more about why some hobbyists will be long term avid aquarists, and why some may only want to try for a short time.

Maybe we should start a conversation about the life span of fish that are suited to first time tank hobbyist vs the long term.

Up to 2 years: Short term (for those who want to try)
Certain nano-fish, like guppies, platies and danios with a life span of 2 years may be ideal for the first timers. Others: Ricefish, blue eye pseudomugils

Up to 5 years: Longer lived fish like tetras and rasboras for the more knowledgeable, since they live up to 5 years. Others: Rainbowfish, Bettas, Swordtails, Corydoras

Long term: Cichlids (angelfish)

I guess most will never approach their choice of fish based upon the life commitment, but I would love to see more fish store servers gain awareness on the value of life rather than the colours.