Setting up a new aquarium

[AlexW.]

I keep hearing people talk about how few people are in the hobby particularly young hobbyists.  I think a big issue is that many people get into fish and have a bad first experience, they then quit forever.  I think we have a plethora of knowledge and experience in this club.  First and foremost I think new hobbyist should be encouraged to ask the rest of us as many questions as they would like.  Don't be afraid to ask a "stupid" question because the most common way we have learned in this hobby is by doing the stupid things ourselves.  There is no sense in letting the fish suffer because of timidity, we all have been there.  That said I thought that if we are fortunate enough to have new hobbyists in the area check out the site before starting we should have a post about how to set up that new aquarium with some of the most common mistakes we have all made.
 
Buying the aquarium
-Buy the largest tank you can afford.  The reason for this is that large aquariums are more forgiving of mistakes.  The larger water volume will prevent you from making too drastic of a change to water parameters when doing maintenance or when you make a mistake.  I started with a 29 gallon, and it is about the smallest I would recommend for a new aquarist.  A 55 gallon would be even better.  I know that a 10 gallon seems like a great idea.  It will easily fit in your kids room or on your desk.  It isn't too expensive if you find you can't hack it, but it is almost guaranteed to fail because one small mistake and the water conditions will swing wildly out of control.  
-Resist the urge to stock your aquarium on the first day.  I know you want fish, we all do.  I can assure you the excitement of bringing home a new fish never goes away.  You won't be able to satisfy that desire by buying fish the first day, but you can ruin the hobby for yourself by spending a bunch of money on fish that are very unlikely to survive the first month.
-Be sure to get water conditioner, a tank cover, light, and a filter of some kind.  A heater is optional for some fish, but if you want the ability to keep the vast majority of fish in the store get one of those too.  
 
Setting up the new aquarium
-Be sure to account for the weight of the new aquarium.  The tank itself has a significant amount of weight, along with the décor, but the biggest weight will be the water.  It is roughly 8 lbs per gallon so if you have a 29 gallon aquarium the water alone will weigh 232 lbs and 55 gallons of water is 440 lbs.  The best thing to do is to set it up on a concrete floor, but if you want it on a second level try to set it up perpendicular to the floor joists.
-Be sure it is level.  If the tank isn't level it can cause stress on the silicone seams between the glass, eventually pulling them apart causing a catastrophic failure for both your house or apartment and the fish.
-Rinse your tank and decorations with water.  Do not use detergent of any kind.  If you feel the need to clean it with something use vinegar.  
-Set up your decorations.  Get them positioned as you like them.
-Fill the tank up with conditioned water by pouring it over a plate so that the water doesn't upset your decorative arrangement and make sure there are no leaks.  I have never had a problem with leaks, but you never know.
-Set up your filter and heater.
-Put in a little fish food once a day for several weeks.  This will start the nitrogen cycle which is the most important part of keeping fish in an aquarium.  The only thing you should be doing to the tank during this time is adding fish food and testing your water.  Take advantage of this time to plan out your ideal stock.  Once the ammonia, nitrites, and nitrates stabilize to acceptably low level then you can go to the next step, and probably the most exciting part of keeping fish.
http://www.startafishtank.com/aquarium-setup/fishless-cycling-cycle-your-tank-with-fish-food-or-ammonia/
 
Buying your first fish
-Research.  One of the best things about this hobby is that you get to learn about all of the fish you are keeping.  Embrace this aspect of the hobby and research species you are interested in before you buy them.  This will save many fish from an untimely death and many hours of frustration for yourself.  You may find that the fish you want will get too big for your tank, or that it is too aggressive to buy right now, or that it has very tricky water parameters, etc.  It is better to get the bad news before you spend the money than after.
-Don't go crazy.  This is probably the hardest thing to do in the hobby.  Do not be tempted to start adding fish too quickly.  Add one or two small fish, then wait for a few more weeks, then you can do it again.  You will continue on like this until the tank is stocked.  This allows the bacteria in your tank to expand their population to be sufficient to process all of the fish waste.  If you expand too fast the bacteria can't keep up, ammonia begins to rise, followed by nitrites and nitrates, followed by dead fish.
-Don't get a monster fish if you have a minnow tank.  Some people think the fish only grows to the size of the tank, while this is true it isn't because it stops growing, it is typically because it dies.  If your red tail catfish lives to the ripe old age of two that isn't a full life for a fish that should live to be 15 years old and grow to 36 inches.  Most people think 'this fish gets to three feet, but I will either buy a bigger tank or give the fish away when that happens.'  Sadly we find that fish grow really fast, bigger tanks are expensive and we have other priorities.  Additionally no one wants to take an eventual monster so they are hard to get rid of even to the pet store that promises to take it back.
-Buy the least aggressive fish you want first.  This allows them to establish themselves before the bullies move in.  That way they know all of the hiding spaces and they feel more comfortable in general.  If they are adjusting to a new home and running from the local brute they will likely not survive the week.
-Know your water.  If your water is naturally high in pH don't go looking for fish from the Amazon, or from a black-water pool.  Instead buy fish like guppies, danios, and African cichlids.  If you are on well water and your pH is naturally low, work with that and go for the Amazonian tetras, and dwarf cichlids to name a few.  The point is don't adjust your water to the fish, select fish for your water.
-Quarantine.  If at all possible set up a quarantine tank, instead of simply adding fish to your main tank.  The reason for this is that fish come from unknown sources.  They may carry disease, and it is much easier to treat a quarantine tank with a few fish than treating you main aquarium.  It is also much less costly to lose only the fish in quarantine than to lose an established aquarium full of fish.
 
Keeping your tank
-Don't clean your tank.  I know it is counter intuitive, but in my opinion where a lot of new hobbyists fail is that they are too eager to provide a pristine environment.  Sure you should vacuum out the excess food and fish waste, but don't go over the top. Don't take your decorations and scrub them down.  Definitely don't remove your filter media and clean it.  The bacteria that you need to keep your tank running are living on these surfaces.  If you clean them off you set yourself back to day one of cycling your tank.  If you have to cycle the aquarium with fish in it they will most likely die.  The proper way to clean filter media is to simply squeeze out the detritus, you can even rinse it in a bucket of water you took from your tank.  Do not rinse it under the sink as your municipal water supply has chemicals in it meant to kill microorganisms.
-Don't clean the glass, even the outside with chemical cleaners.  White vinegar or lemon juice on a sponge will do a great job and it won't have the possibility of over-spraying poison into your tank.
-Many small water changes is better than one big water change.  Keep doing 10% water changes regularly because it will assist you in having a more stable environment for your fish.  The only time you should do a large water change is if you have a problem you need fix, or if you are trying to induce your fish to spawn.  Even when trying to fix a problem I would be hesitant.  The thing to remember is that if you have an issue the fish are stressed, if your water parameters start to become erratic that may push them over the edge and kill them.
-Be consistent.  Keeping an aquarium is much easier if you just keep up with the maintenance.  Fish die when you are forced to treat an emergency situation.
-Have fun.  It is a lot of work at times, but it is really rewarding.  Enjoy yourself and don't be afraid to ask those of us who have been doing it for a while for advice, most hobbyists are happy to give it.
 
Those are my thoughts.  If anyone has other advice, or disagrees with my opinions feel free to pipe up.  I would love to hear your thoughts.