Common Name(s)
Ruby tetra
Scientific Name
Axelrodia riesei
Family
Characidae
Origin
Rio Meta basin in Colombia
Temperament
Peaceful
Maximum Size
0.66 inches
Minimum Tank Size
5 gallons
Tank Setup
Looks best in a planted tank with a dark substrate and background.
Tank Region
Middle-top
Diet
Omnivore. Will take dry foods, but supplement with mosquito larvae and other live foods.
Breeding
Egg-scatterer, doesn't take care of its young.
Compatibility
With other small temp-compatible community fish
Ease of Keeping
Fairly easy
Care
pH: Doesn't matter; Temperature: 75-82 Fahrenheit
ruby tetras.jpg

They are the smaller reddish fish in the back.
Here is a closer picture:
http://www.seriouslyfish.com/wp-content/uploads/2013/03/Axelrodia-riesei-HW-2.jpg

A schooling fish, so should be kept in groups of 6+ of their own species.

Males are more colorful and smaller than females, females are also more round-bodied than males.