Peaceful community fish

Every fish on this page carries the top temperament mark, peaceful. The mark below it, mostly peaceful, covers fish that are fine in most tanks with one known habit. The zebra danio, rosy barb, three spot gourami and the black and sailfin mollies are one step down, so they are not here. They mix with most of this list, and the stocking calculator checks the pairing. Peaceful fish still eat what fits in the mouth, so a community works by size as much as by temper, and it works by water: every species in the tank shares a temperature and a pH range.

1. 01

   The top mark

   Peaceful, not mostly peaceful

2. 02

   Same water

   Every fish shares a temperature and pH range

3. 03

   No mouth fits another fish

   A 2 inch fish is food to a 6 inch one

4. 04

   Three levels

   Top, middle and bottom fish share the tank without a crowd

The rummy-nose tetra is the tightest school in the hobby at 2 inches (5 cm) for 20 gallons (75 liters), marked easy. The black neon tetra is marked beginner at 1.4 inches (3.5 cm). The lemon tetra and the x-ray tetra both stay around 2 inches (5 cm) and take a pH up to 8, so they suit hard water where cardinals do not. The dwarf rainbowfish is marked easy at 2.8 inches (7 cm), one of several rainbowfish that fit a 20 gallon (75 liter) tank. The threadfin rainbowfish is 1.6 inches (4 cm) for 13 gallons (50 liters), marked medium, with fins that any nipper will shred, which is why it lives on a page of peaceful fish.

The panda cory is 2 inches (5 cm) for 11 gallons (41 liters), marked easy, and the cory most shops stock. Sterba's cory is 2.6 inches (6.5 cm) and lists 75–82°F (24–28°C), one of the corys for a warm tank. The pygmy cory is 1.3 inches (3.3 cm) and swims in open water as often as on the sand. The otocinclus grazes algae at 2 inches (5 cm) for 12 gallons (46 liters), marked medium because a new tank has nothing for it to eat. The bristlenose pleco is one of the plecos that stay a sensible size, 4.9 inches (12.5 cm) for 20 gallons (75 liters). The yoyo loach reaches 6.3 inches (16 cm), lists 42 gallons (160 liters) and eats snails.

The marbled hatchetfish lives at the surface, 1.6 inches (4 cm) for 32 gallons (120 liters), marked medium, and it jumps through any gap in the lid. The pygmy hatchetfish is the smaller one at 1 inch (2.5 cm). The golden pencilfish hangs under the surface at 2.4 inches (6 cm) for 18 gallons (70 liters). The glass catfish is marked easy at 2.8 inches (7 cm) for 30 gallons (115 liters) and shows its spine through its body. It schools in the middle of the water column, often facing into the current. The white cloud mountain minnow is marked beginner at 1.6 inches (4 cm) and lists 57–72°F (14–22°C), so it suits an unheated tank. Endler's livebearer is 1.6 inches (4 cm) for 10 gallons (38 liters), marked beginner, and breeds without help.

The discus is marked peaceful and difficult, 5.9 inches (15 cm) for 65 gallons (245 liters) at 79–90°F (26–32°C), a shoaling fish kept in a group of six. The Congo tetra is 3.1 inches (8 cm) for 24 gallons (90 liters), marked easy. The spotted silver dollar is 5.5 inches (14 cm) for 53 gallons (200 liters) and eats plants. The red rainbowfish reaches 5.5 inches (14 cm) and lists 34 gallons (130 liters); the banded rainbowfish 5.9 inches (15 cm) and 50 gallons (190 liters). The uaru is a cichlid marked peaceful, 11.8 inches (30 cm) at 81–86°F (27–30°C), kept in a group of five or more. It lists 65 gallons (245 liters) as a minimum, and a group of adults needs a much larger tank.