Inside the Numbers: How Big Is the U.S. Aquarium Fish Population in 2025?

Aquarium keeping is often thought of as a niche hobby—but the numbers tell a different story. Beneath the tranquil surfaces of living room tanks lies an aquatic world teeming with life. In fact, pet fish quietly outnumber dogs and cats combined in American homes. Let’s take a deeper look at the true scale of aquarium ownership, fish populations, and tank setups across the country.

Pet Fish Outnumber Dogs and Cats?

Yes—by a long shot.

According to industry data, there were nearly 140 million freshwater fish in U.S. households in 2017. Despite a small dip in fish-keeping households since then, the total population in 2025 still sits above 100 million.

For context, there are approximately 68 million dogs and 49 million cats in the U.S. today. Fish may be quiet companions—but they dominate by sheer volume.

How Many Fish Per Tank?

Freshwater aquarium owners tend to keep about 13 fish on average. This includes popular schooling species like tetras, rasboras, or guppies, which thrive in small groups.

Saltwater aquarium keepers, by contrast, often keep fewer fish per tank, instead focusing on carefully curated reef ecosystems that include corals, anemones, and invertebrates. In both cases, aquarists often develop deep knowledge of species compatibility, water quality, and nutrition.

What Size Tanks Do Most People Use?

Home aquariums range from tiny desktop bowls to full-scale, sculptural centerpieces like our 65-gallon rimless aquariums.

A 2024 survey of fishkeepers revealed:

• 46% use aquariums 40 gallons or smaller (great for beginners or space-conscious homes)

• 54% maintain larger setups, from 50 to 200+ gallons

These larger tanks offer greater stability, improved aesthetics, and the chance to recreate complex underwater environments.

Fish Breeding: A Serious Hobby

Fishkeeping doesn’t stop at observation—many aquarists actively breed their fish.

In fact, 66.3% of surveyed hobbyists report breeding at least one species at home.

Breeding can range from raising livebearers like guppies to more intricate efforts with cichlids, bettas, or marine species. It often requires multiple tanks, filtration systems, and detailed knowledge of water parameters, lighting, and behavior.

This statistic reflects a growing trend: many hobbyists are no longer just owners—they’re stewards of small, thriving ecosystems.

What It Means for the Modern Aquarium

The data reveals a passionate, knowledgeable base of aquarium keepers across the country. Whether it’s a small desktop tank or a large, rimless showpiece, aquariums are evolving into more than décor—they’re personal biospheres.

And as tank sizes grow and aquarists deepen their knowledge, the demand for high-quality, American-made aquariums has never been stronger. That’s where we come in. Caldera Haven is proud to offer premium tanks—like our 65-Gallon JBJ Rimless Aquarium—designed for both beauty and biological balance.

Want to Build a Thriving Tank?

Start with the right foundation.

Explore our aquarium collection and discover what crafted calm really looks like.