How to Keep Tropical Fish (Beginner’s Guide)

Every day, people discover the wonderful world of aquariums and tropical fish. Fishkeeping is a hobby that can seem complicated, but it also brings the opportunity to think about and observe countless things we don’t normally see in our daily lives. Having a home aquarium means you also get to see and interact with a micro-universe – One that you created!

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1 What is a Tropical Fish?

When people say “tropical fish,” they’re referring to fish that come from sunny, warm waters (usually between the Tropic of Capricorn and the Tropic of Cancer) where the temperatures are high year-round. This might make most people think of the ocean (and therefore saltwater aquarium fish) but there are plenty of rivers, lakes, and other bodies of water that offer us colorful and vibrant freshwater fish as well.

Generally speaking, we can divide tropical fish into two types: Freshwater or saltwater (also called “marine fish.”)

Choosing one type of fish shouldn’t just depend on whether you find them more or less attractive; each requires different kinds of aquarium, knowledge, and dedication.

Packaged food is a popular and inexpensive type of fish food available in several different tastes and recipes. Below are the popular types of dried food:

2 Tropical Fish Care

The first step is to decide between a freshwater or a saltwater aquarium. This will determine everything that happens after, from the type of fish you buy to the equipment you’ll use.

Keep in mind that an aquarium isn’t made up of only fish. You can include plants, wood/trunks, and even invertebrates in a freshwater aquarium, and a saltwater aquarium can include algae and corals.

Care for both freshwater and saltwater fish is very similar, although saltwater fish can be a little more complex for beginners since you’re also managing salinity. The complexity part is especially true if you are also managing corals, which require a little extra care.

2.1 Aquarium

Choosing the correct aquarium size that’s proportionate to the amount and species of tropical fish you’ll be keeping is crucial in making sure they’re comfortable and healthy. It’s part of the rule of thumb of fish keeping: Recreate a fish’s original natural environment as much as possible.

When in doubt, err on the side of the fish and choose a larger aquarium.

Contrary to logic, small aquariums are more difficult to keep stable for the very reason that they’re smaller; If you make a mistake in water quality, there will be fewer consequences in a bigger tank that is more dispersed.

Other aquarium considerations are location, lighting, and providing the necessary accessories (including a filtration system, water test kit, heaters, etc) to maintain water quality.

2.2 Water Quality

Water quality is the cornerstone for aquarium life. To make sure the water quality remains at a standard high enough to maintain healthy fish, the water parameters need to be tested and checked on a regular basis.

If you’re new to fish keeping, you’ll get used to hearing about water parameters, which include water temperature, pH, water flow, and more. In the case of saltwater fish, you’re also testing for salinity (salt). These should all be tested once or twice a week to maintain a healthy tank.

You’ll learn more about fish supplies as you go! Local aquarium stores are a huge help to newbies, and I recommend local shops over big box stores as you’re more likely to find a seasoned aquarist there.

2.3 Feeding Tropical Fish

Fancy guppy

Fancy Guppy Photo by (c) Karel Zahradka 

Not all fish eat the same thing! Their dietary needs will vary depending on the species and the ecosystem of their natural habitat. Like humans and other animals, you can classify them into three categories: Carnivore (eats meat only), herbivore (eats plants only), and omnivore (eats both plants and meat).

Saltwater fish have a more restricted diet, such as strictly piscivores (which eat other fish; It’s the fish version of carnivore!) or algae eaters. It’s more common for freshwater fish to be omnivores.

For more info on feeding, you can check out our article on what fish eat.

2.4 Tropical Fish Aquarium Maintenance


Aquarium maintenance is essential for keeping the system healthy and stable. A tank with up-to-date maintenance is one in which fish are always colorful and healthy, with behaviors as close to natural as possible.

It’s more efficient to do periodic maintenance every week, but some aquarists do it every two weeks or even months.The frequency depends on factors like the number of inhabitants, filter size, and the species you’re keeping.

It’s absolutely crucial that before and after maintenance, you carry out water monitoring and tests; Most importantly pH and ammonia, and checking the temperature.
If you notice that your water has a strange appearance, like a milky or yellowish hue, unwanted aroma, and/or foam on the surface, these are indicators that the tank needs cleaning and water change.

These are symptoms indicating that the aquarium is already beyond the maximum time between maintenance, and is above acceptable levels of ammonia and other toxic compounds. In this case, you must urgently perform maintenance, preferably changing a large amount of water (around 50 to 70%).

If you see these symptoms repeatedly, it’s a sign that something in your tank is incorrect or imbalanced. Among the many potential causes, the most common are an overpopulation of fish, inconsistent filtration, or even going too long in between maintenance. To figure out what’s wrong (and hopefully fix it!), perform more frequent maintenance and testing until you’re able to uncover the cause. Test very frequently and log the results, and observe the tank and inhabitants for any changes. You can also ask a local aquarium store for input, too, if needed.

After the partial water change, the new water needs to be within the parameters (temperature, pH, and hardness) that you have pre-set for your aquarium. Otherwise, it can cause physiological shocks in the fish; The abrupt change of parameters shocks their system.

Another thing to note is that municipal city water contains elements like chlorine and chloramine. These compounds make the water drinkable for us but are toxic to fish. To remove them, we use a product called a water conditioner. When using the conditioner, carefully follow the manufacturer’s recommendation for use.

To help you with maintenance, always have equipment such as buckets, hoses, and a siphon for the aquarium’s exclusive use. Dry cloths are very good for drying up spills or accidents.

Remember to turn off any aquarium equipment so that it doesn’t break during maintenance (and equally, remember to turn them back on after!)

3 Freshwater Tropical Fish

Cloudy White Mountain Minnow

Cloudy White Mountain Minnow Photo by © Mikhailg

There are thousands of tropical freshwater fish, and many of them are perfect for beginners! Below are some of the most common species.

    3.1 Tetras

    Tetras are known for being a schooling fish with a wide range of colors. They’re a great little fish to have because they’re very active and easy to keep.

    Some species of tetra fish can live for more than 5 years when properly cared for. As they are schooling fish, you’ll love seeing a group of tetras moving around in the aquarium. Note that they are a schooling fish though, and need to be kept with a minimum of 6 of their own kind.

    Otherwise, they’ll become anxious and even get sick.

    Some easy-to-care tetras are neon tetra, cardinal tetra, green tetra, black tetra, congo tetra, and bleeding heart tetra.

      3.2 Bettas

      One of the most famous fish, the Siamese Fighting Fish are intelligent animals and easy to care for.

      Given breeding and selection in captivity, betta fish are available in a multitude of colors and patterns. They are super-resistant fish and can temporarily withstand certain undesirable conditions (such as water with fluctuating parameters or poor quality), so it’s the perfect choice for those who are still starting.

        3.3 Cloudy White Mountain Minnow

        The Cloudy White Mountain Minnow, known as tanichthys, is originally from Asia. Some aquarists call it the white cloud because it’s common on a mountain of the same name in China. They’re also referred to as white cloud minnows, and other variations of this name.

        It has a blue coloring and a reddish back fin, which creates a charming and attractive appearance. They are very peaceful and adapt well to different environments. Being minnows, they live in shoals and should be raised in groups of 7 or more fish.

          3.4 Livebearers – Guppies, Mollies, Swordtails and Platies

          All four of these livebearers are incredibly popular fish among beginner aquarists, as well as those who have been in the hobby for a long time.

          They come in many varieties of colors and shapes, as well as being hardy and peaceful. They breed easily, and if you have a couple, you will always have fry in your tank.

            …And more!

            When I said there were lots to choose from, I meant it! Other popular tropical freshwater fish include corydoras, plecos, and cichlids.

            Cichlids are very popular due to their bright and flashy colors and variations, but beginners should be aware that most cichlids are aggressive or semi-aggressive, and thus require some specialized care and planning around who will live in the aquarium with them.

              4 Saltwater Tropical Fish

              Azure Damselfish Photo

              Azure Damselfish Photo by © Lukas Blazek

              Even if you’re new to the aquarium hobby, you can still keep a saltwater aquarium with a little planning, commitment, and discipline. The biggest difference is that you also have to maintain the salinity properly in addition to the other parameters, but it’s not the only one.
              Temperature control in marine aquariums is also more difficult than in freshwater aquariums. They also have a higher cost because they may need additional accessories, such as a skimmer, chiller, and pump-dosers.

              Corals are a possibility in a saltwater tank, but be aware that they require just as much planning as fish do. They have their own water parameters, requirements, and temperaments, and many of them can release toxins that can hurt or even kill you or your pets. With a little precaution you can be safe, but it’s something to keep in mind

              Lastly, saltwater fish can be more sensitive to changes in temperature and environment, so keep an eye on them. This is because the parameters of the ocean do not vary as much as freshwaters do; They’re more stable, which means the fish can’t handle fluctuations in temperature or pH.

              With these things in mind, let’s check out some of the best saltwater beginner fish.

              4.1 Clownfish

              After a successful Pixar animation, the fame of the clownfish skyrocketed. There’s a huge variety of clownfish, but they’re all very easy to care for. Among the different types and species, some (such as the tomato clownfish) are more aggressive than others and do not get along well with other clown species. Stick with regular old clownfish and you’ll be fine:) They’re friendly and fun to watch in the tank.

              Clownfish will feed well and are very easy to care for. The ocellaris clownfish is probably the most recommended for beginners.

              4.2 Gobies

              Gobies are considered by many to be the best fish for beginners starting a saltwater aquarium, not only because they have several species that are easy to obtain, but because most of them are very calm and easy to care for. A great example of this is the watchman goby.

              4.3 Tangs

              These are the classic fish of saltwater aquariums like the yellow tang and the blue tang (the famous Dori). If you’re looking for a fish that stands out well in your aquarium and has a wide variety of colors, this is a great choice.

              Most species are ideal for larger aquariums (above 55 gallons). Yellow tangs can present ethical issues since most of them are sourced from the wild in Hawaii.

              4.4 Damselfish

              Often considered an aggressive fish, some species of damselfish don’t have much patience with other fish picking fights- Especially when it comes to other damsels. That said, it’s a very hardy fish and easy to keep in your aquarium.

              5 Challenges in Tropical Fish Keeping

              Reef tank photo

              Reef Tank | Photo by © Scaliger

              In both saltwater and freshwater aquariums, there are similar challenges:

              • Maintain water quality.
              • Ensure all fish feed properly and plan the types of feeders in the tank well.
              • Watch for diseases and understand behavioral changes in fish.
              • Know the best equipment and supplies for particular species.
              • Know how to configure and use equipment and tests for total efficiency.

              By reading and studying, any doubts will gradually give way to confidence and acquired knowledge. As with everything in life, keeping tropical fish is something gradual, learned through successes and mistakes.

              One thing to note is that many fish have not yet adapted well to living and/or breeding in captivity. This is particularly true for saltwater fish (yellow tangs, for example). Do your homework on the type of fish you want to keep before running to the store so you know what you’re getting into, and you’ll be fine:)

              6 Tips for Beginners

              If you’re just starting out, it’s a good idea to avoid looking for information from just one source and to apply critical thinking, as well as common sense. There’s a lot of incorrect information floating out there on the internet, and unless you compare it between different sources, you won’t know which one is correct.

              The best tip by far is to keep in touch with other hobbyists through forums, social media, and visiting local aquarium stores; This is the fastest way to become a successful hobbyist. Nowadays you can get in touch with aquarists from all over the world with just a click, so it’s easy to ask questions and gain new knowledge.

              7 Tips for Experts

              Aquarium hobby and fish keeping are activities in constant evolution both scientifically and technologically, so never stop reading about new types of management, species, and equipment.

              My golden tip here is to get out of your comfort zone. Test new techniques, look for new challenging species, try to reproduce that fish that no one has managed yet to date, and with that, document and release access to all attempts, even if they failed.

              That way, you help others who are on the same path as you and give strength to those beginners who hope to one day accomplish the same feat that advanced aquarists can.

              8 Final Thoughts

              Starting in aquarism can feel like a daunting moment in which it all just seems very difficult. Keep reading and researching, and you’ll get there! Having a beginner’s guide to the aquarium hobby is a starting point for setting up an aquarium that will bring you many joys.

              Look for more information about the fish you find interesting, and consider whether they make sense to keep in your aquarium. The ideal fish for beginners are those that are easy to care for and that you feel interested in.

              Things like aquarium maintenance may seem difficult and complex at first. But as you integrate them into your daily life, they’ll become increasingly simple and automatic.