Aquariums can be a relaxing and enjoyable addition to any home that will provide both you and your fish a stable, healthy and happy environment…assuming you know the basics. While it may seem intimidating when first getting involved in the hobby, with a bit of knowledge, you may be surprised at how simple and fun things can be. This guide covers the basics: from tank size, heaters and filters to decorations, cycling and more.
*The information presented here is based on my own personal experience and research as well as information that may be considered common knowledge among aquarists. However, one of the most important aspects of fishkeeping is to do your own research. Always get second opinions before making decisions and remember that just because someone sounds like they know what they’re talking about, it doesn’t mean they are always correct…myself included.
1……Cycling (the Nitrogen Cycle)
15….Fish Food & Feeding
19….Stocking Your Tank
20….Acclimating New Fish
1…Cycling (The Nitrogen Cycle)
Cycling an aquarium properly is the single most important aspect of starting a new aquarium, which is why it’s listed first. Most fish store workers will tell you to let the aquarium run for a week or so and then add fish. This unfortunately is bad advice; letting a tank “run” will not properly cycle the tank. Cycling means growing the correct bacteria needed to consume the toxins (ammonia) your fish put out through waste. Growing these bacteria does take time (1-3 months) and cannot happen in one week.
There are different methods of cycling a tank and colonizing those bacteria and the path you choose is entirely your decision. This will be the most important choice you will make for your new aquarium…so research deeply and choose wisely.
The two basic methods are Fishless Cycling and Fish-In Cycling (including Silent Cycling). There are pros and cons to both forms, so do your research, weigh your options and select the method that fits best with your knowledge, experience level and willingness to be committed to your aquarium.
Before you purchase fish please read the links below and decide which you would rather do. Keep in mind that both methods are valid, however fish-in cycling requires daily commitment to your tank to ensure the safety and well-being of your fish. If you are not able to commit to potentially daily water testing and water changes for 1-3 months please consider fishless cycling.
Fishless Cycling Pros
– No fish are at risk or exposed to dangerous toxins
– Very little maintenance during the process. Limited water changes, adding pure ammonia and testing your parameters is all that’s involved.
– The ability to (usually) fully stock your tank once the tank is cycled instead of adding fish very slowly over time
Fishless Cycling Cons
– Requires patience
– You’ll have an empty fish tank sitting around for a while
Fish-in Cycling Pros
–You can have a few fish in the tank immediately
Fish-in Cycling Cons
–Fish are at risk of ammonia / nitrite poisoning if not properly cared for
–Requires absolute responsibility and dedication in order to keep your fish healthy
–Water changes and testing daily are often required (also there is no such thing as too many water changes during fish-in cycling as long as you are using temperature- matched conditioned water. )
Before purchasing an aquarium, survey your available space and get the largest aquarium you can fit into your home. Why? Believe it or not, larger aquariums are easier to maintain than smaller aquariums plus your options for fish will be increased with a larger aquarium. There is also more room for error in larger aquariums since there is more water to dissipate toxins if something goes wrong.
A good tank size to start with would be a 20 gal long aquarium; fish options are greatly increased with this size tank plus it has a lot of surface area and horizontal swim room for active fish. Most beginners start with a 10 gal aquarium which is fine, however fish options are fairly limited in a 10 gal tank plus the smaller the tank the smaller margin for error.
Also keep in mind the weight of the aquarium on your floor when filled with water, particularly if your aquarium is going to be on an upper level.
A note on Aquarium Kits: The all-in-one kits may be tempting to buy and can be useful however most of the time the filters they come with are barely enough for the tank size. It’s often better (and cheaper) to buy the pieces separately so that you can custom build your aquarium to your specifications.
Quarantine Tank: While you’re aquarium shopping you may want to purchase a 10 gal tank to use for quarantine. If a fish develops illness in your main tank you may want to quarantine it for treatment rather than treating the whole tank. You should also quarantine new fish for a minimum of at least 2 weeks before putting them into your main tank to monitor the fish for potential illnesses to avoid introducing sick fish into your main tank. Also running an extra filter on your main tank, which you can then use to instantly cycle a quarantine tank, is a good idea and can save you a lot of time and frustration if an emergency arises.
Think about the surface your aquarium is going to stand on and be sure that it can hold the weight of a full aquarium. Purchase an aquarium stand built for aquariums or you can even build your own.
Filtration is very important for any aquarium and the more filtration the better. You generally want a higher level of filtration than your tank size; so if you have a 30 gal tank and your filter is rated for aquariums up to 30 gals you may want to invest in a larger filter (or more than one). A good rule of thumb is purchase filtration that is double the size for your tank, so if you have a 20 gal tank purchase a filter that’s rated for at least a 40 gal aquarium.
There are many types of filters: under-gravel (UG), hang on the back (HOB), internal and canister. Most internal and HOB filters are the best choice; canister filters can also be great for larger tanks. Some recommended brands are Aquaclear (HOB) and Fluval (internal or canister).
Most filters come with filter media which is the “stuff” that goes inside the filter; this can be ceramic rings, sponges, pads, etc. Some filters also come with charcoal. There is some debate on whether charcoal is needed for an aquarium. Mostly charcoal is used to remove medications from the water after treating for illness but generally charcoal isn’t needed at any other time. You can keep the charcoal in the filter without any harmful effects but you can also choose to replace the carbon with another form of filter insert such as a sponge or ceramic rings.
Most manufacturers say to replace filter media every x amount of months but this is incorrect. The beneficial bacteria your aquarium needs mostly live on your filter media and replacing the media can cause your tank to recycle depending upon the amount you change. Generally filter media does not need to be replaced until it is literally falling apart (which can be years) and if you do need to replace some filter media replace a small portion at a time.
Gravel or sand? It largely depends on your preference. If you are thinking of stocking your tank with bottom feeders that like to burrow or sift through the substrate (like Khuli Loaches or Corys just for an example), sand may be the best choice.
Sand should be rinsed multiple times or else it will cloud up your tank for a while (and even with rinsing there may be some temporary cloudiness). Pour the sand into buckets and stir it up repeatedly with your hand, dump the cloudy water and repeat until the water runs clear. You can also rinse the sand through a clean pillow cover. Some of the finer sands can get into your filter mechanism and cause issues but this shouldn’t be a reason to forego sand entirely.
Sand also looks more natural than gravel so if you’re looking for a natural-look to your aquarium you may like sand better. Sand is actually easier to keep clean than gravel as gravel offers many small spaces for leftover food and waste to hide and potentially foul the water if not cleaned properly.
Aquarium sands sold at fish stores are fine to use. Many aquarists also choose to use Pool Filter Sand which can be cheaper.
Gravel is easier to prepare: usually just rinsing it off a few times in hot water is sufficient. Some gravel can deteriorate over time where the coloring washes off and you’re left with whitish colored gravel. This probably depends on the brand of gravel you are using although most aquarium gravels should be fine. Gravels come in various colors as well so if you’d like a more colorful tank then you may prefer gravel over sand.
The standard lights that often come with aquariums are sufficient for viewing fish and possibly for growing low-light live plants. Lights should be kept on a day/night cycle as fish require some dark time. Lights can be generally kept on for up to 10 hours per day without any negative effects.
Some light fixtures have a built-in moonlight effect or you can build your own. Moonlights can be kept on for a few hours at night but leaving them on overnight is not recommended.
A Note on Black lights: There are some fish (Glofish for example) that are genetically engineered to “glow” under backlight. While a few hours per day under backlights should be fine for fish this should not be the sole source of light. A standard daylight aquarium bulb should be used most of the time.
A water dechlorinator (or conditioner) is a must-have; it detoxifies the chemicals in your water so that it is safe for aquarium use. Seachem Prime is highly recommended due to the fact that it is highly concentrated and less Prime does the same job as more of most other brands and will therefore last longer. Prime also helps detoxify nitrite and ammonia in an aquarium which can be helpful in situations where toxins are present such as during fish-in cycling. Other similar brands are API Stress Coat, Amquel, API Tap Water Conditioner and Tetra AquaSafe.
Follow the dosing guidelines on the bottle of the dechlorinator you plan to use.
A water testing kit is essential for any fish keeper. You will need to check your water regularly to ensure that all levels are safe for fish and to test the water if you see any problems developing with your fish. A good liquid test kit is recommended as opposed to test strips. Strips are cheaper in the short-term however they do not last long and they are generally inaccurate. The best liquid test kit that is recommended by most hobbyists is the API Master Kit.
If you are thinking of setting up a tropical aquarium, you will need a heater. Be sure that the wattage is enough to heat your size tank but don’t buy a heater that is too large for your aquarium; a 200 watt heater isn’t good for a 5 gal tank as it may potentially overheat your tank if it malfunctions– larger isn’t always better when it comes to heaters. Often the packaging on the heater will tell you how many gallons the heater can support. Also purchasing an adjustable heater so that you can control the temperature is highly recommended. Some good adjustable heaters are Aqueon and Fluval.
You want an in-tank thermometer to ensure that the heater temperature is accurate. Some heaters often heat the water to +/- 1-2 degrees from which they are set so it’s always best to double-check. A mercury thermometer is preferred over the external stick-on thermometers which can be hard to read and often not accurate.
An air stone or bubble wand isn’t a must-have for an aquarium. If you like the aesthetic quality of the bubbles then purchasing an air stone and air pump can be fun and fine to use. As long as your filters agitate the surface of the water there should be sufficient oxygen exchange and an air stone isn’t needed unless you want one. However if your filter fails an air stone can provide an emergency backup allowing oxygen into the water until your filter is fixed or replaced.
If you live in an area where power outages are common you may want to invest in a battery operated air stone (sold at some fishing supply shops and larger department stores in the fishing section) to provide oxygen for the fish until power is restored.
Plastic, silk and real plants are all options. Plastic plants are commonly sold at pet/fish stores and are safe to use, just remove any stickers that may be on them from the stores and soak in hot water before placing in the aquarium. Plastic plants will last for years and are easily maintained by occasionally rinsing them off in old tank water during a water change. Some plastic plants have sharp edges that can injure some fish however.
Silk plants are like plastic plants but softer and they also can seem more life-like as opposed to plastic plants. They too will last a long time and maintenance is the same as they are for plastic plants.
Real plants are often a favorite and can be a hobby in itself. Your aquarium lighting will largely dictate which live plants you can safely grow in an aquarium. Most aquariums come with a single standard T8 florescent bulb which should be able to maintain very low-light plants such as Anubias, Java Fern, and mosses such as Java Moss.
Healthy plants also provide another form of natural filtration as they can consume excess nitrates and toxins in the water…but uncared for plants do more harm than good as rotting plants can contribute to bad water quality which in turn can harm your fish. Also do research prior to investing in live plants: ensure that your lighting is sufficient for the plants you wish to grow and be wary of plants sold at large chain fish stores as most of those plants are not fully aquatic and may rot in your aquarium if left underwater for a long period of time.
Fish can tell the difference between real and fake plants. Many fish use real plants to hide from predators or to spawn (mate) and even lay eggs. Some fry (baby fish) use dense plants such as Moss to hide in until they are large enough to swim among other fish without being eaten.
This is the fun part. There are many types of aquarium decorations from underwater ships to Greek Coliseums and everything in between. As long as the decoration is stated as being aquarium safe it should be fine to use. Just remove any stickers from the store and rinse the decor under hot water before placing in the aquarium. Be wary of using reptile decorations in an aquarium as some may be pre-treated with pesticides; if in doubt, contact the manufacturer prior to placing these in an aquarium.
Natural driftwood is also a choice for many hobbyists who want to create a life-like underwater scene. Mopani, Malaysian and Manzanita are common types of driftwood. Many local retailers and online shops sell driftwood. You will need to soak the driftwood in hot or boiling water in order release the tannins inside the wood; often these tannins will produce a tea color to your water however this is not harmful to fish. It is also normal for natural driftwood to grow a white fungus-like substance for the first few months after it is placed in your aquarium which is not harmful and will go away in time.
Also some natural driftwood will not sink on its own right away but should sink on its own in time. You can attach a piece of slate to the bottom of the wood with aquarium safe silicone or stainless steel screws.
Also keep in mind that some driftwood may reduce your water’s PH in the aquarium, so keep this in mind. You can test the PH of the water that the driftwood is soaking in to see if the PH drops.
Vacuuming the substrate in your tank is essential to removing fish waste and leftover food which can damage water quality (vacuuming often during fish-in cycling has no negative effects on the cycle). Siphons also make it easier to pump the water out of the aquarium for water changes.
There are many siphons to choose from; if you are thinking of maintaining a larger tank (15+ gallons) an automatic water changer such as the Aqueon or Python changer can be useful for larger tanks. These changers connect to standard faucets and eliminate the need for buckets. (If you use a manual changer for water changes you will need to dose the aquarium with dechlorinator prior to adding the water and remember to add enough dechlorinator for the entire volume of the tank, not just the water you are replacing).
15…Fish Food & Feeding
Fish like variety just as humans do. There are many fish foods on the market, too many to go into here. Some of the recommended brands are Hikari and New Life Spectrum. Some fish even like (or require) fresh vegetables. Some bottom feeders such as Corys (Corydoras) should be supplemented with algae wafers or shrimp pellets. There are also frozen foods, sinking foods, pellets, wafers, flakes and many others. Research the best types of food for your fish and try to give some variety. Note that freeze-dried foods are not recommended as they can cause bloating issues in fish; if freeze-dried foods are given they should be used as an occasional treat only and soaking the food in tank water for a few minutes may help combat some of the digestion issues associated with freeze-dried foods.
Regardless of whatever food(s) you choose, overfeeding is very easy to do and can be detrimental to fish health and water quality. Fish always seem hungry but they can be easily overfed which can cause bloating and swim bladder issues. It’s also good practice to fast your fish one day per week so that their digestive tracts can clean themselves out. Feeding your fish a thawed, de-shelled, frozen, unsalted pea once per week can also help them digest their food and combat constipation (just remove any uneaten peas after a few hours).
There is a lot of debate among hobbyists as to whether to use bacteria starters or cycle boosters to aid in cycling an aquarium. Generally they are not needed and in some cases do not work. Some bacteria starters contain the wrong types of bacteria and even if they do contain the correct types it can be very difficult to keep bacteria viable that is kept in a bottle and shipped from place-to-place under various temperature conditions.
If you want to safely add bacteria to your tank to aid in cycling find someone with a healthy established tank and ask them for some of their filter media to place into your filter. If you don’t know of anyone with an established tank, AngelsPlus sells “active” seeded sponge filters from their Angel Fish tanks which have helped many on this forum with their cycles (both fish-in and fishless). Just ensure that the sponge filter you buy says “active” next to it or else you are just purchasing a plain filter.
Aquarium salt is generally not needed in freshwater aquariums (although as with most things in this hobby this point has been debated). Most large chain fish stores will tell you that aquarium salt is required but this is not true. Aquarium salt is only generally needed to treat certain diseases or injury and is not required otherwise.
As you go along you may need to acquire other tools such as medications, breeding traps, etc. depending on your setup and what your aquarium requires. These tools generally can be purchased later if needed but not required at the beginning. Just remember that owning an aquarium is a responsibility so be prepared for the eventuality that you may need to run to the store to purchase something if the need arises.
19…Stocking Your Tank
There is an old-school rule of fish stocking which says that 1″ of fish can be added per 1 gallon of water. This of course would dictate that a 10″ fish would fit in a 10 gallon aquarium, which is just silly. So then what’s the rule? Unfortunately there isn’t one easy rule to follow when stocking a tank. Adult fish size, activity level, bioload, etc. all need to be taken into account when planning the proper fish for your size tank.
For example, since Goldfish are large, messy fish the general rule is 20 gallons for the first goldfish and 10 gallons for each additional fish, so if you wanted 3 goldfish you would need a 40 gal tank. This is just for Fancy goldfish; goldfish like Koi or Commons grow too large for home aquariums and should be kept in ponds.
Neon Tetras are very small fish and are commonly sold so it should be OK to put a group of them in a 5 gal tank right? Unfortunately no. Neons are also very active swimmers and need a good amount of horizontal swim space in order to thrive properly; at least a 20 gal long aquarium would be ideal for these fish.
Choose your fish carefully because you’ll have them for the long haul. For example, if you purchase a school of Tetras and down the road wish you hadn’t bought them you are effectively stuck with your Tetras because they are schooling fish and you will have to continue replacing them if some die off to keep up the minimum number they require for their school.
The best advice when it comes to stocking your aquarium is to do your research first. Search the internet for information on the types of fish you want to keep; check their compatibility with other fish and temperature requirements for each fish (for example, a Coldwater fish like goldfish should not be kept with tropical fish due to the temperature differences they require). Also start a post here on AA asking for advice; your best resource are other hobbyists who have experience with the fish you are wanting to keep and can give constructive advice so that you choose fish that are suited for your size and type of aquarium and will be happy in their new home.
20…Acclimating New Fish
So you’ve cycled your tank and are ready to add fish! You can just plop them into the tank right? Nope. Fish need to be acclimated slowly to your tank because your tank’s parameters (temperature, PH, etc.) can be very different from the tank from which they came.
The “old school” way of acclimating fish is to float their bag for a while in your tank. This only acclimates them to temperature however and not other factors in your water. The best way to acclimate fish to your tank is by drip acclimation (also search YouTube for “drip acclimation” for some how-to videos).
Once your tank is fully cycled and you have the appropriate fish for your tank you will need to maintain the aquarium. The best practice is to change 50% of the water per week. You can do this by doing 2-3 smaller water changes per week or one larger change per week. Also test the water with your test kit every couple of weeks to ensure water quality is good. You want nitrite and ammonia to be 0 at all times and keep nitrates <20 (nitrates are only removed through water changes). Even if your nitrate doesn’t reach 20 during the week between water changes it’s still a good idea to maintain a weekly water change schedule. Fish use up minerals in the water and these need to be replenished. Also clean water can go a long way in preventing disease in most fish. Use your siphon regularly to vacuum the substrate and suck up any excess waste that lies at the bottom.
99% of the time, your natural water source (tap or well water) is more than sufficient to use for your tank as long as it’s properly dechlorinated. If your source water is very high in toxin levels (ammonia, nitrate, etc.) you may need to “cut” the water by using a mix of source water and RO (Reverse Osmosis) water. Please ask for advice before changing your source water; most of the time it is fine and if you already have fish changing their water source suddenly can have negative effects.
Also using nothing but Reverse Osmosis (RO or RODI) water in a freshwater tank is not needed except in very rare circumstances. Keep in mind that if you do need to use RO water, you are basically using distilled water which is not only stripped of toxins but minerals as well and fish need minerals to survive. Therefore you will need to add back the minerals manually during water changes with a product like RO Rite or Seachem Replenish. Again, your source water should be sufficient for your aquarium. If in doubt, ask first.
Periodically check your filters and heater to ensure they are working properly. Once or twice per month swish your filter media in old tank water during a water change to loosen any debris that may be caught in the filters.
–Keep it simple
If you open the cabinet under your aquarium and bottles of pH adjusters, clarifiers, aquarium salts, buffers and other additives fall out…you’re probably doing something wrong.
A healthy, established aquarium normally requires only two things to be added on a consistent basis…fresh water from your faucet and a quality water conditioner / dechlorinator.
The hundreds of products found on the shelves at your local fish store may seem like a treasure trove of goodies to keep your fish happy and healthy…but in reality it often has the opposite effect. Just like when buying fish…look all you want, but don’t bring anything home without thoroughly researching it first.
A note about PH: many new aquarists think that they need to adjust their tank’s PH in order to keep certain fish. In the majority of cases, your fish will adapt to your tank’s natural PH and there is no need to adjust it. In fact, attempting to adjust your PH with chemicals can do more harm than good. Fish require stable parameters and constantly fiddling with your PH can cause fluctuations, which is far more harmful to fish than living in a different PH than they are said to need.
…Which is often easier said than done particularly when something goes wrong with your own aquarium. If a fish is behaving abnormally or looks ill or injured don’t panic and buy the first type of medicine you see. Diagnosing fish illnesses can be difficult and you want to ensure that you are using the correct medication to treat the correct illness. Some medications treat particular diseases or infections and even some illness (like Ich) do not require medications for treatment. If in doubt, start a post in the Unhealthy Fish Section and see if others can help.
Remember that your aquarium is not just a piece of furniture or something new to look at…it is a home for living animals who solely depend on you for their health and survival. Before making any decisions, do your research and gather information from different sources (not just the guy at the fish store). Keep in mind that fish-keeping is not just a hobby…it’s a responsibility.
Follow the steps above and enjoy a healthy aquarium that will last for years.
Note: this guide is also posted in the Getting Started Forum; please post questions there.
- A Guide to Aquarium Accessories and Fish Care
- Adjusting pH in the Freshwater Aquarium
- The Freshwater Quarantine Tank
- The (almost) Complete Guide and FAQ to Fishless Cycling
- I just learned about cycling but I already have fish. What now?!