Can Cardinal tetra Live With Ram cichlid?

This is the pairing the ram's own profile names outright: a peaceful, open water characin able to handle the warm water this fish needs, and it specifically points to the cardinal tetra as one of the two species that qualify. The schooling tetra also does the ram a favour beyond just tolerating the heat, since a shoal nearby signals there is no threat around and helps a naturally shy fish settle.

Both like it warm and soft: 27 to 29 °C and pH 4 to 7 sit inside both species' ranges.

Buy the cardinal tetra in its full shoal, 8 to 10 or more, and keep the rams as a single male or a true pair rather than an unrelated group, since the ram is a poor competitor and needs a tank where it is not fighting for food or space. A 60 litre tank is the ram's own minimum; the wide ranging cardinal shoal wants at least the 54 litres it is measured for on its own, so plan for the larger figure with soft, acidic water, driftwood and shade.