i created the reef in affinity
just cut off a circle at the bottom
and inside a flower shape and warped it at the edges with the anchor points
so that everything has this reef look

for the fish i only made a circle which i deformed
the fin is a triangle and I added an anchor point in the middle at the back and moved it to the center

the other things were only created with the path tool

Red ist Cut

Black is Engrave

Green is Score

IMPORTANT
You have to be very careful with the layer with the fish as the connection is only 1.5mm thick and can break easily
i worked very carefully when painting and often held the fish with one finger

while painting i realized that you can glue it together in 2 versions

version 1
you put all layers together in the same way

version 2
you turn the front and the back side around
then the reef gets this offset structure