Red Ruby Cardinalfish

Red Ruby Cardinalfish benefits from shaded rockwork, small caves and sheltered positions where it can remain out of the brightest light. Ruby cardinalfish names have been applied to more than one closely similar species, so confirm the supplier identification before planning its final aquarium or a group. A quiet, cover-rich setting makes it easier to assess a newly introduced fish.

Offer small, suitably sized marine foods and watch for active feeding near its retreat. Several modest feeding opportunities are easier to manage than a large portion that faster fish capture first. If the fish remains shy during bright daytime feeding, try a subdued-light period while checking that it actually consumes the food.

Choose companions that will neither swallow the cardinalfish nor continually chase it away from shelter. Keeping several does not guarantee peaceful schooling: individual relationships and available refuges matter. Monitor each fish for feeding access and persistent exclusion before adding more.