I would go for a theme of what more likely the fish inviroment is, for example if it is african fish a theme that represents plants, rocks and caves etc. if it is south american it be plants, roots, driftwood etc, look at this for some examples.
scroll up and down look into it see if something like this would be of interest.
I thank you all for your attention and time!
75g/Rena Xp3/Inline Heater/Rena Air 200/Eco-Complete/Current Dual Daylight System
6 Rummy Nose, 9 Ottos, 2 Yoyo Loach, 1 Golden Nugget Pleco, 2 Julli's Cory, 4 Angelicus Botia, 1 Chocolate Kuhli Loach, 3 Ghost Shrimp, 1 SAE, 1 Black Mollie, 1 Redeye Swordtail Mollie, 1 C-Pleco, MTS, Guppy's
Argentine Sword, Amazon Sword, Micro Sword, Xmas Moss, Pennywort, Hornwort, Jave Fern, Baby Tears, Moneywort, Ludwigia, Wisteria, Giant Bacoba, Hygro 'Sunset'