To determine if this fish model is a model of metastasis relevant to cancer or one of simple cell distribution throughout the zebrafish, we compared non-cancerous mouse CFP-3T3 cells cultured on rigid plastic with YFP-B16-F1 cells cultured on rigid plastic after co-injecting at 1:1 ratio into the pericardium cavity of Tg (kdrl:mCherry) zebrafish. The gene discussed is CFP; the disease is cancer.