I answer many questions online about the keeping of fish, so instead of constantly re-writing it, it seemed a good idea to collect this information in one place. In this series I will notate all the information (sufficient for the budding hobbyist!) that I have collected on the keeping of fish and small invertabrates in the home aquarium. I’ll be going through everything I know: how to set up your initial aquarium, care of certain species (only ones I’ve had before), and feeding and long-term maintenance.

Before you get your fish

When looking at getting a fish, many people will think about what kind of fish they want and then try to make that fit with the space they have available. That is, I’m afraid, putting the cart before the horse. Figure out where in your home you want to place this tank, figure out how big you want it to be (bigger is generally better, but more on that later), and how big you can afford. If you want an oscar but can’t place a large aquarium somewhere, you may not be able to have one. Once you have your space figured out, find out what size aquarium will fit in that space, and what you will put it on. Tanks come in fairly standard sizes, and below 55 gallons can be acquired at a reasonable price at dollar-per-gallon sales at Petco. You can also look at places like r/aquaswap, craiglsist, nextdoor, and Facebook marketplace for deals from people getting rid of their tanks. The tank stand must be able to support the weight of a full aquarium, so be sure it is a sturdy piece of furniture, or buy one made expressly for the purpose.

Once your tank is in place at home, you still have work to do and money to spend before you get your fish. You’ll need the following at a bare minimum, which I’ll go into further detail later on:

• Filtration
• Substrate
• Plants
• Light
• Dechlorinator
• Lid
• Heater
• Net
• Food
• Medicines
• Test Kit

These items, as stated, are the bare minimum you need to get by. Some things (like the heater) may not be necessary depending on the fish you’re keeping, but as most people just starting in the hobby get tropical fish, you’ll need a heater. Yes, this is a lot of equipment, but if you want to keep your fish happy, healthy, and watch them thrive, you will need all of this stuff.

Filtration

Filtration comes in many forms, but the main goal of your filter is to be a home for your beneficial bacteria, and filter out any large particles (if it does surface skimming). Sponge filters running on an air pump are some of the simplest and most effective in smaller tanks, but there are more options. Most nano tank kits come with a hang-on-the-back (or HOB) filter. These filters draw water up into a box, run it through some kind of media and allow the water to flow back in. HOB’s are easy to maintain, generally on the less expensive side, and can be hot-rodded to be truly exceptional filters.

Internal filters are a class of filters which are any kind of contained filtration system which is entirely submerged in the tank. These are my preferred filtration system without setting up a sump, which I’ll discuss later. While they do take up valuable tank space, they can still be easily hidden, and filters like the Sicce Shark systems are easy to clean. The Ziss bubble filter is an amazing self-cleaning bio filter which is as close to set and forget as you can get (I use both in my 35g Amazon Puffer tank). There are some cheaper options online, but I would tend to stay away from them as I don’t think they are worth it. I also have found the Aquaclear internal filter to be lacking.

External filtration comes in two varieties for the home aquarist, sumps and canisters. Sumps are a second, smaller aquarium or other container which contains baffles controlling the movement of water to go through various forms of filtration media. This generally starts with the water going though some filter floss, then through the primary biological filtration. The water then goes up and down through a few filter sponges. In salt water aquaria (and some fresh water sumps) the water then goes through a refugium where the water comes through a thick well of filtration sand and where sometimes moss is grown to help strip nutrients from the water. After another filter sponge, there is a final chamber with the heater and return pump. Sumps have a massive amount of filtration in them and are great for large aquaria or for running racking systems, where many small tanks all use the same filter supply and return.

Canister filters are a filtration system akin to a HOB where water is pumped into a container which sends the water through several layers of filtration media (from top to bottom generally) and then pumps it back into the tank. Canisters generally house the heater in them as well. The down side to canisters are they are expensive. While they can be produced at home, I don’t believe the cost to filtration ratio works out in canister’s favor.

In the end, you need to pick a filter which works best for the size of your tank and the kind of fish you are keeping. Messy eaters like pufferfish need much more filtration than your average fish of the same size. Be sure the filter you pick does indeed fit in your tank, or fits on the tank. Your plants should also be considered part of your filtration, as they literally convert compounds toxic to fish into growth and oxygen.

Heaters

Most fish in the aquarium hobby are from the tropics and require water temperature between 75-80 degrees Fahrenheit. You will see YouTuber’s who heat their fish rooms so they don’t have to heat the water but that is a fantasy to most hobby aquarists. I recommend any heater which has enough wattage to heat your tank (most have a size range printed on the package, or your local fish store worker will be able to help you [read here, I don’t know an exact formula]) and one with a readable thermostat. A heater which you can set the temperature and forget it is the best heater. Your heater should be the last piece of equipment you need to think about because it always works. If your water feels chilly and your fish are sluggish, your heater might not be doing it’s job.

Substrate

Substrate refers to any “stuff” that you put on the bottom of your tank. Most aquarists will use pea gravel or sand, or a mix of media. I prefer the look and function of sand, but gravel is just as good. Be sure to use a fine gravel, if you decide to go that route. An ideal substrate would be:

• Crushed volcanic rock.
  • You can get large rocks, put them in a fabric bag and beat it with a hammer.
• A fine substrate like sand which can fill in the gaps and pad the bottom
• A coarse substrate like coarse sand or gravel to root your plants down better.

This gives your bacteria a wonderful place to grow, as well as a good base for your plants to root, and textural variation for the pleasure of your eyes. Other than your filter, your substrate will be the next best place for your bacteria to grow. I also would recommend erring on the thicker side of substrate. The thicker the substrate the more depth your bacteria can grow and the more mulm can be stored which is good for your plants. Further, if you go for a thicker substrate, you can go farther between water changes. This will make your fish-sitter’s job infinitely easier when you go on vacation.

At this time I will discuss a form of filtration I did not mention in the filtration section as I believe it works better here. There are under gravel filters which go below your substrate. Many of the commercially made ones don’t look the best and add large clear tubes into the back of your tank for air movement (similar to a sponge filter), but they do work well. They utilize your substrate as a part of the filtration to keep your water clean. Most filtration methods attempt to clean the water column from one side to another, these clean your water from under the substrate to the column which, in my mind, makes a lot more sense. I am currently designing an under-gravel system which will work with a sump or up into a hydroponic planter box to drain back into the tank. Those designs will be up once I build it.

Net

The humble net: you will need it more often than you think. I suggest getting a small, soft fabric one that is only slightly larger than your fish, and a larger mesh net for pouring your fish through. A good way to move fish from your acclimation system (more on that later) into your tank is to pour the fish from the container through a net and then drop them into the tank. The small soft net is best for moving your fish out, or as I use it, netting ghost shrimp for feeding my puffers. A small net is nice in a community tank so you can grab the fish you want easier. The difference between a sniper rifle and a 500lb bomb if you will.

Plants

Plants are a great subject. In my opinion, if you have a chemical problem in your tank, add more plants. A good base of stem plants is the best to have, they are great background plants that require virtually no input. I bought one pack of 10 stems and the cuttings are now in at least seven tanks across the US. Stem plants are great, ask your local fish store for one and you’ll never not have live plants. I recommend also having a centerpiece plant, just like you have a centerpiece fish. I like having a lily or lotus for my centerpiece. They have big leaves that contrast excellently against the rest of the narrow-leaved plants in my tanks. I use plants like amazon swords and java fern as my filler plants as they are slower growing and add some stability to my tank. I really like growing red plants as they make this great contrast to what we expect plants to do (being green) and all those fish who like blending in with their greens and browns start popping against the red background.

Besides aesthetics, plants solve most chemical problems. Common aquarium plants are essentially weeds underwater, so they are hardy and amazing at converting nutrients and chemicals into growth. The biggest complaint I hear from new aquarists is “oh no I have algae” after all the “I don’t know what I’m doing” questions. The plants we keep are so much better at converting nutrients in the water column and in the substrate into growth than algae is. If you have an algal bloom, cut back the light and add more plants. Generally speaking, your plants can out compete algae for nutrients.

Something not on the mandatory list is fertilizers as I don’t think they are on the “must have” list of fish keeping. Fertilizer helps your water plants grow just like your terrestrial plants. If you can’t afford to, or don’t want to use fertilizers, you will merely need to curtail what plants you use. You will need to stick to cryptacorns and stem plants because they can be okay growing without fertilizers. Plants feed primarily from either their roots or from the water column. If you plant root feeder plants, nearly all of them require you to put root tabs in or a planted aquarium substrate, or both. In your first tank, I’d avoid that. A bunch of stem plants and a crypt will make a good looking tank without needing heavy fertilization.

Food

You of course need to feed these fish you have, and some fish have specific dietary needs. There are many prepared foods out there you can feed your animals, but I don’t recommend them. I don’t think processed foods are a good form of diet for your animals. For most fresh water animals you can feed a mix of frozen blood worms and brine shrimp which you can get at your local fish store. Most fish you will keep will be ecstatic to get blood worms and brine shrimp; their colors will be better, and they will have a better life. The best choice would be to give live foods all together, especially if you are keeping primary predator fish (such as puffer fish). If you want to keep these kinds of fish, please look for my puffer fish paper coming up soon.

For your primarily herbivore animals, the prepared foods option gets a lot better. Algae tabs come in all kinds of varieties and I have noticed no real difference between feeding prepared foods and real food. This may be because our herbivore pets tend to spend their free time grazing away on algae, biofilm, and leftover food you drop in for your other fish. You can also give blanched vegetable slices and you will have hours of enjoyment watching your horde of shrimp turn a pumpkin slice into nothing.

Light

A light is an important object, not just for your plants but for your fish as well. When the light is on it will simulate daytime for them and they will come out and live their normal lives and you can enjoy them from across the room. Your plants will also appreciate getting to turn sunlight into growth, and your tank will be happier as they will suck out toxins. What light to get though? Any full spectrum LED light that fits your tank really. The more expensive app- or remote-controlled lights are great, and have hundreds of functions but you don’t need that for a beginner. Just get a full spectrum light (one that has white, blue, red, and green bulbs) and a timer. Since my whole house is rigged up with smart lights and Alexa, I have my lights set on timers to come on an hour after sunrise, and off at sunset. You can use analog timers as well, but remember to adjust them as the seasons change or you will find your tank (if it’s in your bedroom) waking you up an hour before dawn.

Medicines

As time has progressed, more and more aquarium fish are being bred in tanks instead of being caught in the wild. Though some are still wild caught, even tank-bred fish can bring diseases with them from the overcrowded breeding facilities in some less-than-reputable breeders. All I will say is, keep the Aquarium Co-Op Quarantine Meds Trio (still not sponsored) around all the time. When you set up a new tank, add all the fish at once and dose those meds as recommended on the bottle and you’ll have healthy, happy fish.

Dechlorinator

Dechlorinator is an additive that neutralizes the chlorine and chlorimide in your tap water to make it safe for fish. They generally also do some other good stuff like aid in slime-coat development and the like. You have to have it unless you live on a well (which could bring other issues) or want to gas-off your water all the time. I use Tetra, but they all do the same thing. Find a brand you like and run with it.

I will take this moment to discuss other chemicals you’ll see on the shelf at your local fish store. I would say unless you’re running a marine tank, 99% of the time you don’t need this stuff. If you have a chemical imbalance, add more plants first. Upgrade your filtration, change your water change routine, add more substrate. There are many things you can do before trying the chemical route. The chemical route will only continue to work while you add the chemicals to your tank. Think of them as a band-aid instead of getting what you really need which is stitches.

Test Kit

A test kit is just as essential as everything else here, plus you get to play at scientist. The API test kit is the gold standard for the hobby aquarist and is fairly cheap and will last a long time, plus it comes in a convenient carry box. Read the instructions carefully and then do tests frequently when you first set up your tank. Ideally you do a test once a week or at the mid-point of your water change cycle, just to ensure your nitrogen cycle is still doing well, but over time you’ll be able to see when things are off without testing. When you first set up your tank and you’re cycling it and you’re getting it all ready, that test kit will get a lot of use. You need to be measuring every few days so you can watch your nitrogen cycle get going. After the tank has been running a year, you probably don’t need to be using it as much.

Lid

The humble lid that probably came with your tank kit (unless you were thrifty and got one without on sale in which case you need to get one). I’ve used press-and-seal or cling film in a pinch, but lids serve a vital role in your aquarium: keeping the water in the tank. Yeah it keeps the fish in there too, but at a normal beginner’s 10 or 20 gallons, you probably won’t need need that. The lid is mostly there to ensure your water doesn’t evaporate too quickly and you have to top off every few days like I did two summers ago. I was losing about an inch of water a day, so keep that lid on. I also live in a dry climate and it was over 100 outside most days, so if you don’t live someplace like that, you won’t get quite as much evaporation. I would still put a lid on that tank.