What fish can I keep?

Find freshwater candidates for your tank size and water conditions.

Freshwater planning for 8 reviewed fish. Each profile links to its care source; check the complete care needs before buying.

Coverage & planning method

Tank lengths and heights, group suggestions, beginner classifications, narrowed ranges, and some volume thresholds are conservative editorial choices. Rasbora ranges center on the source’s targets. These are screening rules, not tolerance limits or a total stocking capacity. The larger aquarium directory includes fish without reviewed care data.

Your aquarium

Fish to consider

Betta

Betta splendens

5+ gal · 16+ in long · 78–82°F · pH not reviewed · Check local stock water

Keep one betta. Community housing is temperament-dependent; use a larger planted tank. Gentle filtration.

Read the care source ↗
Does not fit these inputs
  • Temperature is outside the planning range

Guppy

Poecilia reticulata

10+ gal · 20+ in long · 76–78°F · pH 7–8 · Hard water

Plan for breeding. Mixed groups need two to three females per male; same-sex groups avoid most population growth.

Read the care source ↗
Candidate — review full care

    Southern platy

    Xiphophorus maculatus

    10+ gal · 20+ in long · 70–82°F · pH 6.8–8.5 · Hard water

    Three is a suggested social group, not a schooling requirement. In mixed groups, use at least two females per male and plan for fry.

    Read the care source ↗
    Candidate — review full care

      Zebra danio

      Danio rerio

      20+ gal · 30+ in long · 65–75°F · pH 6–8 · Soft to hard water

      Active schooling fish: use a long tank with open swimming room. Avoid slow, long-finned companions.

      Read the care source ↗
      Does not fit these inputs
      • Temperature is outside the planning range

      Ember tetra

      Hyphessobrycon amandae

      10+ gal · 20+ in long · 72–82°F · pH 5.5–7.5 · Soft to moderately hard water

      Small shoaling fish. Keep six or more with gentle flow and tiny foods. The planner uses 10 gallons rather than the source’s smaller specialist setup.

      Read the care source ↗
      Candidate — review full care

        Harlequin rasbora

        Trigonostigma heteromorpha

        10+ gal · 20+ in long · 74–78°F · pH 6.8–7.4 · Soft water

        Keep a school of six or more. Planning ranges center on the source’s 76°F and pH 7.2 targets; they are not biological tolerance limits.

        Read the care source ↗
        Does not fit these inputs
        • Needs softer water in this planner

        Unknown hardness and missing pH data need a separate check. Matching ranges do not guarantee compatibility. These tools do not assess disease, sex ratios, plants, filtration, or a tank’s biological maturity.