All species

Molly

Poecilia sphenops

Also called mollie, mollies.

Likes hard water. Struggles in soft, acidic tanks.

What it needs

Grows to
8 cm
Smallest sensible tank
110 L, at least 75 cm long
Temperature
23 to 28 °C
pH
7 to 8.5
Hardness
12 to 30 dGH
Kept in
groups of 3 or more
Temperament
peaceful
Eats
omnivore
Swims
at every level
How hard
easy

These are the figures the stocking advice is built on. Make a room and it will tell you whether molly fit the tank you have.