your first aquarium
The most common mistake first time aquarium buyers make is buying an aquarium that is too small. In general, you should never buy anything smaller than 6 gallons. The sweet-spot for beginners is the 10-20 gallon range. A 12 gallon setup is ultimately only a bit more expensive than a 6 gallon setup. A total cost-estimate for the aquarium and everything you need in it (except the fish) is at the end of this page. Read on to get to it, or click here.
Go bigger than 10 gallons
Bigger aquariums have many advantages. Fish tend to sicken and die less – more water means that when things go wrong with water quality, it happens more slowly, giving you time to do something about it. It is also less stressful for fish. In a smaller aquarium, they feel trapped, much as a human stuck in a small room would. There is also less room to hide when you need to invade the water for cleanup or other maintenance. It also means many more options for you when it comes to selecting plants, decorations and additional fishes. The absolute minimum is one gallon per inch of fish, but you should keep some extra margin. Incidentally, fish length for this purpose is based on the length of the body only - don't count the fin length. Most beginner fish are 1-2.5 inches, and are social or schooling fish – they like the company of their own kind, and get stressed without it. 12 gallons will give you room for about 6 of them, which will keep them happy and a joy to watch.
Be partial to acrylic
Aquariums can be made of acrylic plastic or glass. A 12 gallon acrylic aquarium can cost around $100, where a 12 gallon glass aquarium costs $30. If you can afford it, go with acrylic instead of glass. They are lighter, clearer, don't shatter, and don't leak. They are more prone to scratching, but not as much as one would think. Never, ever use any household cleaner or alcohol on acrylic as it will make the plastic fog over.
Buy a system, not just a tank
You should seriously consider buying a fully contained system, such as Marineland's 12 gallon Eclipse. It will come with everything you need to operate it – airpump, filter, lighting and biological medium. There is also a special stand you can order with it. Of course, you can pickup any table you like as long as it can support the weight – water is heavy. Petsmart, Petco, Walmart all carry stands you can look at – always buy one rated for or above the number of gallons your aquarium has. Budget about $50 for it. Also, because tanks are very tough to move once filled, mull where you're going to put yours before you actually install it.
Buy a heater
With an aquarium system, you just need to add gravel, water, water conditioner, fishes, a heater and a thermometer. For a 10-20 gallon aquarium, you will need a 50 Watt heater (cost around $25). Heaters have temperature settings, but they are almost always inaccurate. So, you definitely need a submersible thermometer (cost around $4). Plan on some hit-or-miss tweaking with the heater setting to get the temperature right. Most beginner fish do excellently around 75°F.
Get enough gravel for a 2-inch thick layer
Gravel is important and cheap, so buy it. Plan on a 2 inch deep layer at the base of the aquarium, which usually means buy one pound for every gallon. A 10 pound gravel bag costs around $4. Muted or natural surroundings relax fish, so avoid red and other glowing colors. Black, dark blue or natural mixes are great. Gravel is also important because beneficial bacteria begins to grow in it and maintain aquarium health for you. Always wash the gravel before you put it in the tank.
Buy decorations to comfort the fish
Decorations are important because they give fish places to hide. To a fish, hiding doesn't mean a hole or tunnel, but just something it can use to conceal itself from what it perceives to be a predator. A real or fake plant that it can duck behind counts. Reverse psychology works here. A fish that knows it has the option to hide actually tends to use it very little – it will swim around fearlessly in the tank. A fish in bare tank, however, will cower in fear behind the heater or in a corner. If you buy a fake plant, try to get one with silk leaves. Hard plastic branches can hurt fins. Decorations can cost $5-20. Don't put in any old plastic thing into your tank, unless you yourself would be comfortable drinking from it – many plastics have chemicals that can poison the water. Avoid using wood, because wood also leaches substances into water and can rot. You can buy aquarium-suitable wood ornaments from your pet store. They won't rot, but they are expensive and must be left in a separate pool of water for 1-2 weeks to allow them to bleed-out some color and tannins. Fake plants are a good choice to start out with. Live plants are a better choice once your tank has cycled, as they then have nitrates in the water that they can use for food.
Use tap water with conditioner, don't adjust the pH
Use regular tap water in your aquarium. Do not attempt to change the pH of the water. Anything in the 6.5-8.5 range is fine, and the vast majority of people get tap water in this range. Most beginner fish do fine in this range, as long as the pH isn't erratic. If you use salts to tweak the pH or try and blend tap water with purified water, you will have difficulty maintaining a pH over time – and it will make water changes painful for you. The one thing you should do before adding water is to condition it to remove chlorine and chloramines which are added by the water company to sterilize the water. It's usually two drops for every gallon you add, and a bottle comes for around $7. The drops remove these chemicals instantly, so you just add the drops, stir the water and add to the aquarium. Conditioner is the only chemical you should use in your tank or tank order. Nothing else is necessary. If you are adding water to a tank that has fish in it, try to make the tap water temperature close to the tank water's temperature. Fish are stressed by sudden thermal changes, much as humans are.
Buy basic food for the fish
Fish food is extremely cheap. Buy one bottle each of fish flakes ($4) and freeze-dried bloodworms (also $4). The fish flakes are standard fare for the fish, and the bloodworms (the word sounds more horrific than they actually look) are a special treat. Do not buy live bloodworms as they can bring disease to your tank. One big reason for why water chemistry goes bad in fish tanks is overfeeding. Wasted food sinks to the tank floor and then rots. Plan for a fish to eat one full flake per inch of its size everyday, and not more. It usually says on the can what kind of fish the flake is good for.
Buy a bucket and a net
There are some accessories you should buy and have at hand. The first is a bucket that you will use with your aquarium and nothing else. The ideal size for this is 2-3 gallons with markings to indicate volume. Buy it from any old supermarket. The second is a net to capture fish with ($4). You should net fish only when necessary – netting always hurts them, even if you can't see it. Fish have no eyelids, so their eyes are especially prone to injury when they scrape against the net. Netting is also stressful because the fish essentially acts like it is fleeing to evade death. It will slam into tank walls and hurt its fins squeezing through tight spaces as it tries to get away. The best way to capture them is to use the net to coax them into a container that you also hold immersed in the water.
Buy an aquarium vacuum
You should also buy an aquarium vacuum ($8), which is a grand name for what is actually just a length of plastic tube with a wider cylinder at one end. You use this for water changes. Basically, the cylinder goes in the tank and the water flows through the tube into your bucket. You should change 15% of the water every week. In a 12 gallon tank, that's about 2 gallons being changed a week. Do not use the “up-and-down” pumping instructions that the vacuum will come with to make the water flow. That risks injuring any fish that somehow manages to get close to the vacuum. The better way is to coil the entire tubing cleanly so that it is easy to uncoil later. Immerse it entirely in the tank water, so almost all the air bubbles out. Plug the narrow end with one finger and bring it out of the water and into the bucket (which should be on the floor, and lower than the tank), and remove the finger. Gravity will make the water flow – no pumping needed. To stop the flow, lift the cylinder-end out of the tank. It is simple as can be. Switch the aquarium pump off when you do this – some pumps will burn-out in a minute or two if the water level goes even a little lower in the tank. Remember to add conditioner to the new tap water you put in. Fish sometimes look visibly refreshed after a water change.
Get the aquarium running before you buy fish
Buy your aquarium and the other stuff mentioned above a day or two before you buy the first fish. The tank should be filled with water and humming a day before the fish arrive at your home. Always start with two fish, or at the most three. Never any more. And do not add any more fish until you have proof through chemical testing that your tank has cycled.
Consider buying the three basic chemistry tests
You should seriously consider buying three sets of tests ($8 each) – on each for ammonia, nitrites and nitrates – to monitor water quality. Of course, your local fish store will almost always test these for free (especially if you bought your tank, accessories or fish from them). Still, it's nice to be independent to do regular checks on your own, especially when your tank is cycling. You need a tiny amount of water to do the tests, and should take it in a disposable plastic cup that's been rinsed out and kept for this specific purpose. The tests are easy but take 5 minutes to run. Be careful not to get the stuff on your hands and remember to wash them afterwards.
Soap is a killer
There is a last important thing to be aware of. Soap and detergent, even in tiny trace amounts, is extremely harmful to fish. Do not use them to clean anything that can ever come into contact with the fish's water. You can wash your hands with soap before you put them in the tank, but rinse them thoroughly in running water to make sure they are completely soap-free.
Let's do a quick estimate.
That's about right. The two places you can save here is by switching to a glass aquarium, and using a table, desk or counter you already have for a stand. But don't go below 10 gallons. If you can't afford it yet, wait, save, and buy it when you can. The effect happy fish have on people is difficult to describe. A flat-screen TV can cost you six times as much, and ultimately give you only one-sixth the pleasure. Fishkeeping is actually quite an amazing bargain.