So, I ended up with a new 55 gallon, this was to replace one of my old tanks, if the sanitize from the rainbow, suspected TB did not go well, it seems to have... leaving me a brand new 55 gallon tank, and no place right now to put it... 30 years ago, I did try a brackish tank, along with a handful of salt water tanks... this was before the internet... now I'm thinking something like @WhistlingBadger 's, where I could do a few mud skippers on the land part, and a few brackish fish, in the water part, and following my normal theme, add a handful of mangroves... I don't have a place for the tank, until Mrs. gets sick of looking at it, empty, against the wall in the dining room, so nothing happening right away, but open to suggestions in the build, and stocking areas, for the future...