Is it possible since I’ll use it with fluid simulation for water and or blood
I think you are talking about volumetrics, the thicker the geometry, the darker the colour, there are a lot of tutorials out there, but you have just to connect a Volume Absorption shader in the volume of the material and start tweaking the values of course a glass shader, or whatever, in the surface
Are you rendering on the GPU?
Then be aware that anything volumetric will totally kill your render times, as that’s currently only possible to render on the CPU…
many ways to get this effect
and there is a transp based on ray lenght
Take a look at this node setup using the ray length: