The Essentials

The first thing to understand about keeping fish is that you're not just keeping fish. You’re creating an aquatic ecosystem centered around your fish. While it might seem simple, a mature fish tank is far more complex than just a bowl of water with a fish in it. Due to the diverse nature of life on Earth, there are a variety of processes happening in the tank that you might not immediately notice.

The Waste Challenge in Fishkeeping

It’s easy to forget that fish are living organisms—they breathe, eat, and yes, they produce waste. While fish poop isn’t as much of an issue, their waste in the form of ammonia is a serious concern. When a fish breaks down protein for energy, ammonia is produced and quickly released into the water through the gills. In nature, where the fish-to-water ratio is large, this isn’t an issue. But in an aquarium, the limited space means ammonia can build up quickly, which can be harmful to your fish.

Think of it like a fart in a stadium versus a crowded elevator—the same amount of ammonia will be far more concentrated and dangerous in a smaller space. This is why larger tanks are better suited for small fish, as they offer more room for waste to dissipate.

The Key to Safe Fishkeeping: The Nitrogen Cycle

So, how do you keep fish alive and healthy in a confined space? The answer lies in your tank's microbiome—specifically, the beneficial bacteria in the filter. These bacteria consume ammonia, converting it into nitrite, a less toxic compound. Then, another type of bacteria converts the nitrites into nitrate, which is nearly non-toxic to fish in small quantities. This process is known as the nitrogen cycle and is critical for maintaining a safe environment for your fish. Understanding this cycle is essential for creating a sustainable aquarium that supports healthy fish life.

Experience vs. Science in Fishkeeping

If you’re new to fishkeeping or if you’ve had fish in the past, much of the information on this site may be new to you, and some of it may challenge what you thought you knew. However, one of the most important aspects of responsible fishkeeping is to be able to embrace new information, even if it contradicts personal experience. Just because you’ve kept a betta without a heater for years doesn’t mean it’s ideal for the fish. Fish need specific conditions to thrive, and ignoring these needs can lead to health problems.

The same goes for tank size. If you’ve kept a goldfish in a small tank for years, it's likely that the fish didn’t thrive, even if it survived. While some fish may be able to survive in suboptimal conditions, they won’t be truly happy or healthy. Surviving is not thriving, and when it comes to pets, we should always aim to provide the best care possible—not just the bare minimum.

The Importance of Proper Tank Size and Setup

A recent study from Thailand found that betta fish need a certain minimum tank size to thrive, and that decoration and enrichment are crucial for their wellbeing. Sadly, bettas have often been kept in small, bare tanks, sold as “low-maintenance” fish. But this isn’t just about bettas—it applies to every fish species. Every fish has specific needs, and failing to meet those needs will result in stress and poor health for the fish.

Just as we would never keep a human in a cramped, uncomfortable space for long periods, we shouldn’t expect fish to thrive in suboptimal conditions. A well-maintained tank with proper water quality, temperature, space, and enrichment will help your fish thrive—not just survive.