It's ok.
But you do have a few algae problems: are you using ro/di water? that will help, given time---if you've been using tap, it takes a while to get the minerals reduced. Also try to use frozen food rather than flake...better yet, make those crabs/snails work for a living and don't feed unless you have something that has to have it.
If you have a window nearby, don't open the curtain.
Those trees do frag easily. Then you'll have two---one with the crab, one set where you want it.