I wanted to improve my starfish, but finally I ended up with a pretty different version, so I upload it as a separate blend instead of updating the other one. Actually I made everything from scratch. I painted the texture myself (sort of) in 8k resolution (4k in this blend), added a volume scatter for the light ray effect and fake caustics with a semi transparent texture. I'm pretty happy with it. I could still spend another week tweaking around, but it's time to move on. Hope you like it :)