Transfer fish pattern on cake top with piping gel. Use tip 12 and yellow icing to pipe circular lines for body. Use tip 5 and white icing to pipe dot eye. Use tip 3 and black icing to pipe dot pupils. Use tip 12 and green icing to pipe bead gills, fins and tail. Use tip 5 and orange icing top pipe bead mouth. Use blue icing to pipe tip 12 dot bottom border and tip 5 random dots on cake top and sides.