All of my tanks have some sort of theme, in one way or another. Two of them at dark age era, with the castles and darker gravel. One of them is more hawaiian themed, with tikis and a couple of small plants. One of them is from China, with a pagoda and red and white colored gravel. One of them is natural themed, with a plastic piece of driftwood. One of them is Mayan themed, and another Incan. One is ruin themed, and the last is underwater, such as a sunked ship. I LOVE doing the different themes, as it makes me feel like I'm literally going around the world in my own room :P Good luck with yours.
Ahhh, I see Well I like Atlantis and I have a mild obsession with Deserts(long story)....So I'd vote for those
Though, some new ideas...hmm....Forest theme? Yin Yang theme for a divided 10? Reef theme?
Just random ideas off the top of my head
I have a fall theme going on with Kovu's tank.
He has this autumn looking tree thing in there, a orange fake plant, and a bridge.
It reminds me of a park during the fall season =P
So I think seasons are a neat thing to do.
I really like the forest idea!
maybe even doing household rooms like the kitchen, bedroom, living room, etc..
Or even the outside side of a house. Like, you could have a mini house in there with a yard that includes trees, bushes, a playset,and whatever else :3
None of my tanks are exactly themed, but I love fantasy themes, such as castles, dragons and so on. My five gallon tank has a castle in it, and I've been on the lookout for more things that would go with it. My lfs had a tank set up with a wild west theme and that one looked very cool. They had multi-colored gravel placed so that it looked like roads between the saloon and sheriff's office. Too neat.
I have always wanted to try a space theme:
Pale sand (moon sand!)
Fake crystals or spaceship decorations
Going off of one person's idea already, you could do 4 tanks with a different season in each!
dark rocks with orange/brown plants for autumn.
lush green plants and maybe green or brown rock for spring.
white rocks for winter, etc, etc for summer.
that'd be neat. especially with all the tank right next to eachother!