Sand is the substrate. Could the meds have affected them?

Actually, I only use carbon when removing meds, so this can't be it. What I meant was that I did a waterchange and added carbon to remove old meds, before trying a different treatment.

First let me say that this is a great forum and I am so glad to have found it! I recently lost 4 cories within days of each other (2 pygmies and 2 pandas). All had the same symptoms.....sluggish, whirling, loss of equilibrium, lying on their side, and finally....death :cry: This 3 year-old planted ...