Ahhhhh! the tetra tank plan appeared. I wanna see something more... unusual... than that for such a great sized tank. Something that people aren't gonna see every day. some odd stuff so to say.
for starters, it's 3 feet long, over a foot wide, and over a foot tall. isn't that 50ish US gallons?
A: live plants. that;s a start. plants can do a lot for the tank. onions and val for the back corners so they cna grow up and decorate. along the back use some kind of sword, and through the middle make some kind of spread out wisteria forest.
B: Let's talk filtration. hopefully we've got around 200-400 total gallons per hour cycled?
C: Fish.
Mid dwellers
A1: angels. You have a tallish tank. we could get a pair or three.
or
A2: A school of 6 rainbows of some kind
Bottom
B: Senegal or del Bichir. The gravel looks big enough to where he might not accidentally swallow it.
C: Catfish - 3 Hoplo's? A synodontis of some sort perhaps?
bottom/side
D1: Plecos - some kind of 4-8 inch pleco. Snowball, Clown, Candystripe, Queen Arab, King tiger, Flash, Bristlenose. There are tons to choose from!
D2: Farowella(twig catfish) - only if you plan to keep up with filtration.
So here's what I think
1x Senegal bichir
1x Featherfin syno.
1x Bristlenose (cheap and available most places)
and either
6x rainbow fish
or
2x Angels (marble and koi are cool)
That would be a start. After you plant it, set out territory, and so forth, there would be room for perhaps
A: Some kind of hard to keep fish like a baby whale or elephant nose. but you'll have to keep good track of your water!
B: A pair of kribensis. doesn't look like they can pick on anything here, but nothing should pick on them!
enjoy!