I keep White Cloud Mountain minnows (Tanichthys albonubes) which are very popular aquarium fish or starter fish for children here in Japan. These fish are hardier than guppies which can be prone fungal problems. They can live to 5 degrees Celcius without heating which is another big plus.
The White Cloud minnow fish are native to China. They will grow to about 4 cm.
There are several varieties, but they are usually a silver green colour and a bright red fin, and a light colour to the edges of fins(White Cloud minnow) or red edges to fins (Meteor Minnow variety – see photo to the left).
Other interesting facts:
White Cloud minnows co-exist well with other fish and are in fact comfortable in schools and so should be kept in at least a group of at least five. A lone minnow will become nervous and lose its bright colour.
The minnows like to keep to the top or middle-level and rarely swim close to the bottom of the tank.
They breed easily, and like to scatter eggs freely among the seaweed or aquatic plants and the eggs hatch within 48 to 60 hours.