I have two RES and one will not eat cuttlebone.
Any ideas on how to ensure they get their calcium besides cuttlebone?

Someone on the forum had an interesting idea of lightly coating their food with low sugar jam (to make it sticky) and sprinkling calcium powder. I might try this but unsure if the jam is unhealthy for them.

How about supplements that get added to the water like Exo-Terra Calcimize. The idea being they get their calcium as they drink the water.