beckfords pencilfish

What Are Dither Fish?

Reading Time: 2 minutes

Imagine you’re a fish for a second. You’re small, you’re scared, and you’re easy and delicious (to other fish) to eat. You probably wouldn’t want to come out of your home unless you had to. Great survival strategy, really, it is – but it makes for a bad aquarium display. You would make a terrible pet. 

Suppose for a second you’re the same scared fish, only this time you had some fish out in the open around you. They wouldn’t be out in the open if there were predators around – and there they… are out in the open. Seeing them tells you there’s nothing around that’s going to eat you. At least not something that will eat you before it eats them, anyway. Since the movement of shoaling fish (or in more rare cases in freshwater schooling fish) attract more attention and risk predation than you – as one lone fish – ever could.

More apt to come out now? Me neither. I’m an indoor fish, myself. But it works for actual fish. 

Dither fish are those fish that tell scared, skeptical, or otherwise easily spooked fish that it’s safe to come out. When they’re not around, they know it’s time to hide. Some fish like having dither fish around, but other fish need them around otherwise they may not even come out to eat and will – literally – stress themselves to death. Some of the latter types are kribs and some apistos. Although most dwarf cichlids will certainly appreciate the addition of dither fish. 

Examples Of Dither Fish

Any small, peaceful, upper-water shoaling fish species will do so long as they have comparable water parameters to the fish you’re going to keep them with. Some common dithers include:

Neon tetras are shoaling fish from the Amazons that are best kept in groups of six or more to be happy. They’re not usually nippy and are active and outgoing if housed properly. They prefer blackwater setups but will do fine in a range of parameters. It’s worth noting that commonly available stock isn’t as healthy or hardy as it used to be even ten years ago.

pH: 4.0 – 7.5
dKH: 1 – 12
Temp: 70 – 83F (21 – 28C)
Size: 1.5″ (4 cm)
Temperament: Peaceful shoaling fish
Swimming: Mid to top

pH: 4.0 – 7.5
dKH: 1 – 12
Temp: 70 – 83F (21 – 28C)

Size: 1.5″ (4 cm)
Temperament: Peaceful shoaling fish
Swimming: Mid to top

black neon tetra

Black Neon Tetra (Hyphessobrycon herbertaxelrodi)

Not to be confused with the black tetra (or “black skirt” tetras) or neon tetras (Paracheirodon innesi,) the black neon tetra is a separate species from both of the tetras mentioned. They do best in groups of eight or more – but more is always better when it comes to shoaling fish. They have the peaceful demeanor of the neon tetra without all the health issues. 

pH: 5.5 – 7.5
dKH: 4 – 9
Temp: 73 – 81F (23 – 27C)
Size: 1.5″ (3 cm)
Temperament: Peaceful shoaling fish
Swimming: Mid to top

pH: 5.5 – 7.5
dKH: 4 – 9
Temp: 73 – 81F (23 – 27C)

Size: 1.5″ (3 cm)
Temperament: Peaceful shoaling fish
Swimming: Mid to top

Ember Tetra

Ember Tetra (Hyphessobrycon amandae)

Ember tetras are bright, fun, tiny, shoaling fish that occur in South American black waters. They’re hardy, peaceful fish that are often described as active, bold, and playful. They also enjoy a planted tank, but be mindful that they do like to swim in open space, so be sure to include that in your layout. They enjoy their numbers a little higher than most shoaling species, 8 is recommended.

pH: 5.5 – 7
dKH: 1 – 10
Temp: 68 – 82 F (20 – 27 C)

Size: 3/4″ (2 cm)
Temperament: Peaceful and active
Swimming: Top to midwater shoaling

pH: 5.5 – 7
dKH: 1 – 10
Temp: 68 – 82 F (20 – 27 C)
Size: 3/4″ (2 cm)
Temperament: Peaceful and active
Swimming: Top to midwater shoaling

beckfords pencilfish

Pencilfish (Nannostomus sp.)

Pencilfish is a genus containing 19 currently recognized species. Some popular options are diptails, Beckford’s, and coral. Although it’s a large genus, the care is similar for all of them and you should aim for a shoal of at least six. 

Research into a specific species and their requirements is strongly recommended. 

pH: 5.0 – 7.0
dKH: 4 – 12
Temp: 74 – 82F (23 – 27C)

Size: 2″ (5 cm) species dependent
Temperament: Peaceful
Swimming: Mid to top

pH: 5.0 – 7.0
dKH: 4 – 12
Temp: 74 – 82F (23 – 27C)
Size: 2″ (5 cm) species dependent
Temperament: Peaceful
Swimming: Mid to top

leopard spotted danio

Leopard Danio

Leopard danios have amazing color and, if you look hard enough, you may even be able to find some dazzling color morphs of this fish as well! They do best in groups of six or more and zip around the tank quite a bit, so ensure you have swimming space for a schoal of this size. 

pH: 6.0 – 8.0
dKH: 2 – 20
Temp: 64 -75F (17 – 23C)
Size: 2.4″ (6 cm)
Temperament: Active
Swimming: Mid to top

pH: 6.0 – 8.0
dKH: 2 – 20
Temp: 64 -75F (17 – 23C)

Size: 2.4″ (6 cm)
Temperament: Active
Swimming: Mid to top

Lampeye killifish

Norman's Lampeye Killifish (Poropanchax normani)

Norami killis, or Norman’s lampeye killifish, are non anual killifish (meaning they won’t die in a year) from Central and West Africa. It’s best to get these guys in schools of nine or more to see them at their best. Their blue “eye” nearly glows in the dark and is spectacular to see in person!

pH: 6.0 – 7.0
dKH: 4 – 15
Temp: 73° – 78° F (23° – 26° C)
Size: 1.6″ (4 cm)
Temperament: Peaceful, generally active
Swimming: Mid to top

pH: 6.0 – 7.0
dKH: 4 – 15
Temp: 73° – 78° F (23° – 26° C)

Size: 1.6″ (4 cm)
Temperament: Peaceful, generally active
Swimming: Mid to top

clown killis

Clown Killifish (Epiplatys annulatus)

Clown killis, also called rocket killis, are a beautifully colored little fish that come from slow-moving waterways in southern Guinea. They’re usually quite outgoing, but make sure you buy at least eight of them so they can display their social behavior. 10 is even better.

pH: 4.0 – 7.0
dKH: 1 – 8
Temp: 68 – 79F (20 – 26C)
Size: 1.3″ (3 cm)
Temperament: Usually peaceful and active
Swimming: Mid to top

pH: 4.0 – 7.0
dKH: 1 – 8
Temp: 68 – 79F (20 – 26C)

Size: 1.3″ (3 cm)
Temperament: Usually peaceful and active
Swimming: Mid to top

harlequin rasbora

Harlequin Rasbora

Harlequins are a shoaling species that prefer friend groups of six or more. They’re not known to be nippy fish and are quite peaceful as long as they’re provided plants and company of their own kind.

pH: 5 – 7.5
dKH: 1 – 12
Temp: 70 to 83 F (21 to 28 C)
Size: 2″ (5 cm)
Temperament: Peaceful
Swimming: Mid to top-water shoaling

pH: 5 – 7.5
dKH: 1 – 12
Temp: 70 to 83 F (21 to 28 C)

Size: 2″ (5 cm)
Temperament: Peaceful
Swimming: Mid to top-water shoaling

Further reading & Sources

PSU.edu – Studies On The Shoaling Behavior Of Fish

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