In my humble opinion, the diversity in marine aquarium types is at an all-time high. I’ve always been turned on by the idea of biotope aquariums. The freshwater folks have certainly embraced aquarium themes, even beyond the biotope or species tanks. They base their tanks on various inspirations, including famous terrestrial landscapes or beloved paintings. With the rise of NPS systems, we are seeing deviations from the typical mixed reef or sps-dominant aquarium. Minimalist Aquascapes are also on the rise, and I’ve even seen my share of cold-water tanks.
Another trend that is gaining popularity is the Marine Planted Aquarium. People have dabbled with macroalgae in displays since the 80’s, and seagrasses have been tried by hobbyists for years. But now, there is enough agitation that people are amassing collections of unique macroalgaes and devoting systems to them. While they are certainly great systems for seahorses and pipefish, they also offer an interesting live backdrop for less reef-friendly fish such as butterfyfish and other corallivores. It might break the biotope mold to add corallivores, but a heck of a lot more interesting than just a FOWLR.
Macroalgae are available in a variety of species, shapes, and colors. There are plenty of vendors who offer them during the warm seasons. Many are very attractive. You may not have room to devote a whole system, but you may discover the opportunity to turn an existing refugium into a display of it’s own.
I have been growing a variety of Caulerpa in one of my reefs, alongside corals. I haven’t experienced any ill effects from terpenoids or overgrowth. I do my best to prune the algae regularly, and find it a welcome addition to the tank. Recenty, a friend sent me some turtle grass seedlings to try. The seedlings are so much easier to start out with, since they root themselves and appear to adapt quickly to captive conditions. They do not share the delicate nature that full grown turtle grass transplants are reputed to have. I hope such seedlings become readily available to hobbyists in the future.