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Nano fish for small tanks

Nano species stay under about 3.5 cm. They make a small tank look busy without overloading it, but still need stable, clean water.

  1. Assassin snail

    Anentome helena

    A yellow-and-brown striped predatory snail kept to control bladder, ramshorn and trumpet snails; it breeds slowly and never becomes a pest.

    1 in · 3+ gal · 70–81°F · pH 7.2–8

  2. Bladder snail

    Physella acuta

    A small left-coiled snail that usually hitchhikes in on plants; a self-fertilising hermaphrodite, so a single one starts a colony.

    0.6 in · 1+ gal · 63–84°F · pH 7–8

  3. Malaysian trumpet snail

    Melanoides tuberculata

    A cone-shelled snail that lives in the substrate and stirs it; it breeds without a mate and gives birth to live young, so it fills a tank fast.

    1 in · 2+ gal · 64–77°F · pH 7–8.5

  4. Celestial pearl danio

    Danio margaritatus

    A tiny, pearl-spotted danio with orange fins, the star of planted nano tanks; shy, with males sparring constantly.

    0.8 in · 13+ gal · 72–75°F · pH 6.5–7.5

  5. Crystal red shrimp

    Caridina logemanni

    The red-and-white bee shrimp, benchmark of the shrimp hobby; it needs soft, acidic, very stable water, usually on aquasoil and RO water.

    1.2 in · 6+ gal · 68–77°F · pH 5.5–7

  6. Ember tetra

    Hyphessobrycon amandae

    A tiny fiery-orange tetra for nano and planted tanks; very peaceful and schools in the middle and upper water.

    0.8 in · 13+ gal · 75–82°F · pH 5–7

  7. Endler's livebearer

    Poecilia wingei

    A tiny, brilliantly coloured cousin of the guppy that suits nano tanks of 10 gallons, but crossbreeds readily with ordinary guppies.

    1 in · 13+ gal · 75–86°F · pH 7–8.5

  8. Pea puffer

    Carinotetraodon travancoricus

    The smallest freshwater puffer, an inch of curiosity and attitude; it eats snails, nips fins and rarely suits a community tank.

    1 in · 5+ gal · 72–82°F · pH 6.8–8

  9. Pygmy cory

    Corydoras pygmaeus

    The smallest cory at about an inch, schooling in open water as much as on the bottom; a natural fit for nano tanks with shrimp.

    1.2 in · 13+ gal · 72–79°F · pH 6.4–7.4

  10. Thai micro crab

    Limnopilos naiyanetri

    The smallest freshwater crab, with a shell under half an inch; fully aquatic and peaceful, it lives in floating plant roots alongside shrimp.

    0.4 in · 6+ gal · 79–82°F · pH 6.5–7

  11. Chili rasbora

    Boraras brigittae

    One of the smallest aquarium fish at under an inch: bright red with a dark stripe, made for planted nano tanks with shrimp.

    0.8 in · 13+ gal · 77–82°F · pH 6.5–7

  12. Scarlet badis

    Dario dario

    A tiny, under-an-inch scarlet fish for nano tanks; it eats mostly live and frozen foods, and males split the tank into territories.

    0.8 in · 13+ gal · 64–79°F · pH 6.5–8.5

Every tank is different. Set yours up once (size, water, who already lives there) and each species is checked against it.

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