TankBud

Nano saltwater fish

A nano reef runs on gobies. The fish here stay under a few inches, suit a 10 gallon tank or smaller and mostly leave corals alone, which makes them the usual choice for a pico or a desktop reef. Most are cleaner, clown or dwarf gobies. The dwarf seahorse is the one that wants a tank of its own. Each profile lists adult size, minimum tank and reef safety.

At a glance

Tank size
5–11 gal
5 gal (19 L) to 11 gal (40 L); half the list needs 11 gal (40 L) or more
Temperature
72–79°F
22–26°C, most of the list
pH
8.1–8.4
Most of the list
Difficulty
19 easy
2 medium · 1 difficult
Reef safety
19 reef safe
3 reef safe with caution

22 species

Start here

Gobies for a 10 gallon reef

The neon goby is the fish this list is built around, 2 inches (5 cm) in 11 gallons (40 liters), marked easy and peaceful, and a cleaner that picks parasites off anything that will hold still. The red head and broadstripe cleaner gobies are its Caribbean cousins with the same habits. The yellow and green clown gobies perch in branching coral at 1.6 to 1.8 inches (4 to 4.5 cm) and carry a coral caution for that reason, since a pair may lay eggs on the branches. The tiger goby is a 2 inch (5 cm) fish that sits on the rock and darts for food. All of them list 11 gallons (40 liters), which in practice means a well filtered 10 gallon reef.

The rule

What makes a saltwater fish nano

Every fish here stays under 2.4 inches (6 cm) and lists 11 gallons (40 liters) or less, which is what a desktop reef can hold. Most are marked reef safe outright; the clown gobies carry a caution. Small fish carry no reserves, so they need feeding at least twice a day with food small enough to swallow, and a tank this size has no buffer against a missed water change. The dwarf seahorse is the exception to everything: marked difficult, it wants a tank of its own with live food and almost no flow.

  1. 01

    Under 2.4 inches

    Every fish here stays under 6 cm

  2. 02

    11 gallons or less

    Every profile lists 40 liters or under

  3. 03

    Mostly reef safe

    The clown gobies carry the one coral caution

  4. 04

    Feed small and often

    Twice a day, with food that fits the mouth

Pico

Dwarfgobies and pygmygobies for a 5 gallon

The Eviota dwarfgobies and the Trimma pygmygobies are the smallest fish in the catalog, 0.8 to 1.4 inches (2 to 3.5 cm), and they list 5 to 10 gallons (19 to 38 liters). They are marked easy, peaceful and social, so a small group works, and they spend the day perched on rock and coral picking at pods. They are short-lived and best bought young. The citron and redlined pygmygobies are the colorful ones; the blackbelly and Queensland dwarfgobies the smallest.

Special cases

The cool one, the shy one and the seahorse

The Catalina goby is the nano fish that does not want a heater: it lists 59–72°F (15–22°C), a temperate range that a tropical reef cannot give it, and it is marked medium for that reason. The whitecap goby is a shrimp goby for 11 gallons (40 liters), marked medium because it is shy and easily starved. The dwarf seahorse stays at 1.4 inches (3.5 cm) in 5 gallons (20 liters) and is marked difficult: it needs live baby brine shrimp several times a day and a tank with no competitors. The Elacatinus cleaner gobies, the barber and the yellowline sponge goby among them, are the easy end, and a pair will often spawn in a nano tank.

By the numbers

Smallest

  1. 01
    Blackbelly dwarfgoby (Eviota atriventris)

    Blackbelly dwarfgoby

    Eviota atriventris

    0.8 in (2 cm)
  2. 02
    Brahm's dwarfgoby (Eviota brahmi)

    Brahm's dwarfgoby

    Eviota brahmi

    0.8 in (2 cm)
  3. 03
    Lachdebere's dwarfgoby (Eviota lachdeberei)

    Lachdebere's dwarfgoby

    Eviota lachdeberei

    0.8 in (2.1 cm)
  4. 04
    Queensland dwarfgoby (Eviota queenslandica)

    Queensland dwarfgoby

    Eviota queenslandica

    0.9 in (2.4 cm)

Largest

  1. 01
    Catalina goby (Lythrypnus dalli)

    Catalina goby

    Lythrypnus dalli

    2.4 in (6 cm)
  2. 02
    Neon goby (Elacatinus oceanops)

    Neon goby

    Elacatinus oceanops

    2 in (5 cm)
  3. 03
    Red head goby (Elacatinus puncticulatus)

    Red head goby

    Elacatinus puncticulatus

    2 in (5 cm)
  4. 04
    Tiger goby (Tigrigobius macrodon)

    Tiger goby

    Tigrigobius macrodon

    2 in (5 cm)

FAQ

Common questions

What fish can live in a 5 gallon saltwater tank?

The dwarfgobies and pygmygobies, which list 5 to 10 gallons (19 to 38 liters), and the dwarf seahorse if you can feed it live food. A single one of the 11 gallon (40 liter) gobies is a stretch.

What fish can live in a 10 gallon reef?

The neon goby, the clown gobies, the tiger goby and the other cleaner gobies all list 11 gallons (40 liters). Two or three small gobies is a full 10 gallon tank.

Are nano gobies reef safe?

The dwarfgobies, pygmygobies and cleaner gobies are marked reef safe. The clown gobies carry a caution because they live in branching coral and can irritate it.

Can I keep more than one goby in a nano tank?

The dwarfgobies, pygmygobies and cleaner gobies are marked social and do well in pairs or small groups. Two clown gobies of the same species usually pair; add different species one at a time and watch them.

Do nano saltwater fish need a heater?

Yes, at 72–81°F (22–27°C) for every fish here except the Catalina goby, which lists 59–72°F (15–22°C) and needs cool water.

Is a dwarf seahorse a beginner fish?

No. It is marked difficult and it starves without live brine shrimp offered several times a day. Keep it in its own 5 gallon (20 liter) tank with gentle flow and something to hold on to.

Index

All nano saltwater fish

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