Sounds like you came from 12D, they have underwater parties I'm told.
They were always happy like you too, so much so, they were called Euphorics.

Idk but the memory is the same.
I just walk around under water without breathing equipment.
There is an older man who seems to be either my father or grandfather with me along with another being that looks somewhat like an octopus, but a being. It is not an animal or fish of any kind but another breathing speaking species of conscious being. All telepathic.

They are taking me to some sort of underwater mountain. He is explaining to me that there is something that has to be done to Gaia every so many yrs. He is telling to me that he has to be the one to do it because only a certain bloodline can do what ever it is.

I never really understand exactly what it is that has to be done but I do understand that he is trying to gently tell me if he fails then it would fall to me being his only linage. While I am not sure of which relation he is, I know that he is my only family & the whole thing is a bit upsetting. When we get to the mountain it ends.