Fish Species Finder — Best Fish for Your Tank

Not sure what fish to get? Answer a few questions about your tank size, water and experience, and we'll recommend the best freshwater fish for your aquarium.

What are you hoping for? (pick any)

Recommendations are a starting point based on tank size, water, and temperament. Always confirm care needs and quarantine new arrivals.

How to choose the right fish for your aquarium

The best fish for your tank is one that fits your conditions, not just one that looks good in the store. Before you buy, match four things:

  • Tank size — every species has a sensible minimum; a fish that outgrows its tank will never thrive.
  • Water — soft and acidic, neutral, or hard and alkaline. Pick fish that suit your tap water rather than fighting it.
  • Experience — some fish are bulletproof for beginners, others need stable, mature tanks.
  • Goals — algae control, a colorful centerpiece, an active school, or a breeding project.

The finder above weighs all four and ranks species that fit. Then check they get along with our Compatibility Checker and that you have room with the Stocking Calculator.

Best beginner fish by tank size

A few reliable starting points for new fishkeepers:

  • 5–10 gallons: a single betta, a school of chili rasboras or ember tetras, cherry shrimp, or nerite snails.
  • 20 gallons: guppies, platies, harlequin rasboras, neon tetras, and a group of corydoras — the classic peaceful community.
  • 40 gallons and up: bristlenose plecos, dwarf and pearl gouramis, angelfish, and dwarf cichlids like kribensis.

A 20 gallon is widely considered the easiest starter size — enough water to stay stable, but still manageable.

Common beginner mistakes to avoid

Set yourself up for success by sidestepping the classics: adding fish before the tank is cycled, buying "common" plecos or fancy goldfish that quickly outgrow a small tank, overstocking on day one, and impulse-buying fish that aren't compatible. Plan first, stock slowly, and quarantine new arrivals.

Choosing Fish — FAQs

What fish should I get for my tank?

Choose species that match your tank size, water type, and experience level, and that suit your goal — whether that's algae control, color, or a peaceful community. Use the finder above for ranked recommendations tailored to your setup.

What are the best beginner fish?

Hardy, peaceful, forgiving species are best to start with: guppies, platies, mollies, harlequin rasboras, neon tetras, corydoras catfish, bristlenose plecos, and bettas. Cherry shrimp and nerite snails are great low-maintenance additions.

What fish can I keep in a 10 gallon tank?

A 10 gallon works best with one small focal point plus a nano group: a betta, or a school of chili rasboras or ember tetras, often alongside cherry shrimp or a nerite snail. Avoid fish that grow large or need to be in big schools.

What's the best fish for a 20 gallon tank?

A 20 gallon opens up a true community: livebearers like guppies and platies, a school of tetras or rasboras, and a group of corydoras on the bottom. A dwarf gourami or pair of dwarf cichlids makes a nice centerpiece. Run your picks through the finder for specifics.

How many fish should a beginner start with?

Start with a small group — just a few fish — even if your tank could eventually hold more. This keeps the bioload low while your filter matures. Add more in small batches over the following weeks once your water tests stable.