An aquarist is a person who keeps, cares for, or studies aquatic life in a controlled environment. That could mean a single betta in a 5-gallon (19 L) tank on a desk, a reef aquarium full of corals and colorful fish, or a garden pond stocked with koi and water lilies. Some aquarists work professionally in public aquariums, research labs, or fish farms, but most are hobbyists who simply enjoy bringing a little piece of the underwater world into their homes.
The word comes from “aquarium,” which itself comes from the Latin aqua, meaning water. You will also hear the terms “fishkeeper” and “aquarium hobbyist” used in much the same way. Whatever you call it, the heart of the hobby is the same: creating a healthy, stable home for living things that depend completely on you.
What Does an Aquarist Actually Do?
Keeping fish is far more than dropping food into a tank once a day. A good aquarist is really a caretaker of an entire small ecosystem. Day to day, that usually involves:
- Managing water quality. Fish live in their own waste, so aquarists test for ammonia, nitrite, nitrate, and pH, and carry out regular partial water changes.
- Understanding the nitrogen cycle. Beneficial bacteria turn toxic waste into safer compounds. Establishing this cycle before adding fish is one of the first lessons every new aquarist learns.
- Choosing compatible species. Not every fish gets along. Aquarists research adult size, temperament, diet, and the tank size each species needs.
- Feeding properly. Herbivores, carnivores, and omnivores each need a different diet, and overfeeding is one of the most common causes of poor water quality.
- Maintaining equipment. Filters, heaters, lights, and pumps all need occasional cleaning and checking.
- Watching for problems. Spotting changes in behavior, color, or appetite early often makes the difference between a quick fix and a lost fish.
The Main Types of Aquarist
Most people start in one area of the hobby and many later branch out into others. Here are the main paths.
Freshwater Aquarists
Freshwater is where the majority of hobbyists begin. The fish are widely available, generally affordable, and often forgiving of small mistakes. Popular choices include tetras, guppies, corydoras catfish, gouramis, and cichlids. Many freshwater aquarists also grow live plants, creating lush “planted tanks” or carefully designed aquascapes.
Explore our freshwater fish guides for species profiles, or start with our list of easy aquarium plants for beginners.
Saltwater and Reef Aquarists
Saltwater aquarists keep marine fish, and many go on to build reef tanks with corals, anemones, shrimp, and other invertebrates. Marine systems need more attention to salinity, water chemistry, and lighting, but the reward is some of the most vivid color found anywhere in nature. Clownfish, gobies, blennies, and tangs are all favorites.
If you are thinking about taking the plunge, our guide to the easiest saltwater fish for beginners is a good place to start, and you can browse hundreds of species in our saltwater fish guides.
Pond Keepers
Pond keeping takes the hobby outdoors. Pond aquarists care for koi, goldfish, and native species, along with marginal and floating plants. Ponds bring their own challenges, such as seasonal temperature swings, predators, and algae, but a well-balanced pond can become the centerpiece of a garden. Visit our pond care guides to learn more.
Specialists
Some aquarists focus on a single group of animals: breeding shrimp, raising discus, growing coral frags, keeping brackish species, or maintaining biotope tanks that recreate one specific river or reef. Specialists often contribute real knowledge back to the hobby, documenting breeding methods and care details that help everyone else.
Professional Aquarists
Outside the home, aquarists work in public aquariums, zoos, universities, and conservation programs. Their jobs can include caring for large exhibits, quarantining new animals, running breeding programs for threatened species, and educating visitors. Many professionals began exactly the way hobbyists do: with a small tank and a lot of curiosity.
How to Become an Aquarist
You don’t need a qualification to become a hobby aquarist, just patience and a willingness to learn. A simple path looks like this:
- Research first. Decide whether freshwater, saltwater, or a pond suits your space, budget, and time.
- Start with a reasonable tank size. Counterintuitively, a 20 to 30 gallon (75 to 115 L) tank is often easier than a very small one, because larger volumes of water stay stable for longer.
- Cycle the tank before adding fish. This usually takes several weeks.
- Choose hardy, beginner-friendly species. Add them slowly rather than all at once.
- Build a routine. Regular testing, water changes, and observation are what keep an aquarium healthy over the long term.
- Keep learning. Every species has its own needs, and experienced keepers are always picking up new tips.
Why People Love Being an Aquarist
Ask any aquarist why they do it and you’ll hear a range of answers. Watching fish is calming, and many people find a tank helps them unwind after a long day. Others enjoy the problem-solving side: balancing chemistry, designing aquascapes, or finally getting a difficult species to breed. For families, an aquarium is a hands-on way for children to learn about biology and responsibility. And for many, it’s simply the beauty of a thriving underwater world that they created themselves.
Join the Aquarist Community
No aquarist learns alone. Whether you have a question about a cloudy tank, want advice on stocking, or just want to share a photo of your latest setup, our Aquarist forum is the place to connect with fellow fishkeepers at every level.
Ready to dive in? Choose your path: