Reduction of rbm24a or rbm24b results in aberrant vasculature and a lack of vascular maintenance. TG(kdrl:G-RCFP) zebrafish line was used to asses the impact of rbm24 depletion on vasculature at 48 hpf and 72 hpf. Lateral views are shown for whole embryo, heart and trunk with a dotted outline indicating heart chamber boundaries. Uninjected controls at all time-points display looped hearts and properly developed vasculature. (A, D, G, J, M, P). 48 hpf rbm24a morphants possess unlooped hearts but display only the PCV and stunted disorganized Se (B, E, H). 48 hpf rbm24b morphants possess unlooped hearts, and only the DA and CV are visible with disorganized Se (C, F, I). By 72 hpf there was increased vascular disorganization and degeneration and a lack of heart looping and in both rbm24 morphants (K, N, L, O, Q, R). Cardiac morphant phenotypes are displayed quantitatively as percentages; Normal, looped beating heart with no cardiac edema; Class I, looped beating heart with cardiac edema. Class II, unlooped beating heart tube with cardiac edema, Class III, beating heart cell mass with cardiac edema; Dead, extreme cell death and degradation of embryo (S). Morphant vascular phenotype classes; Class A, disorganized trunk vasculature with formed DLAV; Class B, disorganized trunk vasculature with truncated Se and no DLAV; Class C, no discernable PCV; Class D, no discernable DA or CV (T). v, ventricle; a, atrium; DA, dorsal aorta; CV, caudal vein; PCV, posterior caudal vein; Se, intersegmental vessels, DLAV, dorsal longitudinal anastomotic vessels; IV, intestinal vasculature.