susieq

I realize that a lot depends on where you live.....or where you are trying to make the fukien tea live, such as in your house, but where I live (in Florida) they are anything BUT fussy. Three years ago I planted a bunch of them in the ground along the North side of my house, in very poor, sandy soil and pretty much ignored them for most of the year and yet they live and grow uncontrolably..... I throw a little time release fertilizer on them when I remember. I finally got around to cutting them back two weeks ago so I could see what if any, trunk development is going on.

Even during the drought that we have been having, they do not show any ill effects and I do not water them very often. I don't even cover them in the winter when we are under frost or freeze warnings anymore..... I have always said you can carry this over fussing too far and kill a plant with kindness.
Even so, I know it is not an easy thing to keep them indoors. I wish you luck with that.

With regard to the aquarium water, as long as you are not treating your fish with any chemicals for disease, there is nothing in the water that will hurt your plants. It is just mild natural fertilizer and very beneficial. I used to save all the water changes from my two very large aquariums and water the trees with it.
susieq