Welcome to Tropical Fish Keeping forum. Glad to have you with us.
It has been more than 40 years since I was in school
and my projects were never as interesting as this can be. It even has me excited, thinking about the opportunities this presents.
One suggestion would be a biotope aquarium. A biotope is a tank that replicates a specific watercourse, be it a stream, lagoon, pond, swamp or lake. Fish in the tank would be native to that watercourse, as would any plant species. Decor, being the substrate (sand, gravel), wood and/or rock would be what is found in that watercourse. A 10g is limited space, so small fish will work better because you can have more of them for a more active and interesting aquascape while still being authentic.
As the fish and plant (if any) species will likely be the most restrictive in terms of what may be available locally, consider the available fish and research their natural watercourse. Find out what substrate, wood/rock and plants might be found in that watercourse. If you can obtain the live inhabitants locally, it will be much easier to build the biotope.