Not nano, but a possible biotope for filefishes, like tassle fiefish, Chaetodermis, or sargassum (segrass or bristletile) filefish, A. tormentosa.
Both are described living in seagrass covered places, hunting there for a food.
Do you know, how to grow macroalgae fast in their tank (they are omnivores, algae eating too), without lowering pH by CO2 injections, avoiding growth of undesirable algae - the fish produces a lot of waste and small particles and dissolved organics during feeding. Also, they seems do not like bright light, necessary for the plants.

Any thoughts?
If you have a small mimic filefish, looking like valentini puffer, this should be similar.
If you have any photos or links, post, please.