The weird stuff in my tank

[avilamillar]

Hey I have found this in my tank and took some pictures for you to see it. I'll appreciate if someone could help me with the ID.

Jellyfish? Cassiopeia Andromeda?



Blue Caulerpa?





Some kind of Coral?



Baby snails? they're tinny. Collinista? Nerites(I've nerites' eggs everywhere)

They only come out at night and stay on the lower part of the glass that I dont clean and on the shells of my clams







This is a bigger one(still pretty small) Collinista?



Also saw this guy releasing eggs/sperm last night. Nassarius?



Thanks