While it is often the brilliantly colored coral or captivating saltwater fish that draw us into keeping a marine tank, there really is a variety of different and unique biotopes or "types" of tanks you can create. These biotopes are aquariums built with the specific purpose of keeping a particular species or type of flora or fauna inside of them. This could be a seahorse tank, an NPS coral tank, an aggressive fish tank with Lionfish or Groupers, and believe it or not, even algae.  Yes, you heard it right, some folks grow algae on purpose, Macroalgae to be specific.  

This is the very first episode of a NEW tank build series in which our host, Remy, is going to walk us through a complete setup of a macroalgae-dominated reef aquarium. These macroalgae tanks can be incredibly simple but also quite captivating, allowing you to keep some interesting creatures and learn about a lesser-known side of saltwater aquariums. Let's explore some of the reasons why you might consider a macroalgae tank for your next salty project!

Remy's Display Refugium Kit

What Is A Macroalgae Display?

Macroalgae is a little different than that pesky green or brown stuff that coats the walls of your tank or blankets the rocks and ruins your day. As defined by biologists, Macroalgae is a collective term that refers to larger benthic (attached to the bottom) marine algae species; colloquially called seaweed. Sharing much of the same characteristics as plants, it is easy to see them as saltwater plants and, in fact, a macroalgae tank ends up strikingly similar to an untamed freshwater planted aquarium.

While most hobbyists think of macroalgae as a tool for a refugium and nutrient export, we are not talking about chambers hidden away down inside your sump or tank stand. Instead, we are going to explore macroalgae dominant aquariums where different species of macroalgae are mixed together to create something beautiful, worthy of display.  Often called "display refugiums" or macro tanks" by hobbyists.

Shop Algaebarn Live Macroalgae

Why Macroalgae?

Just like plants and coral, macroalgae looks cool and creates a natural scene you could easily encounter in the wild. It comes in a variety of colors with many shades of green, deep red, and purple. There is an even wider variety of shapes, sizes, and textures. Some macros are tall and some are fat, some are curly but grow real flat. Some are fuzzy and grow in a mat! What do you think of that, Cat in the Hat?

Ok, Dr. Suess references and unnecessary rhyming aside, macroalgae is super easy to work with in terms of scaping or planting in your tank. It also grows relatively fast (compared to coral) and it can quickly fill in an entire scape with a spectrum of color and shapes in only a fraction of the time it might take your mixed reef tank.

Macroalgae can grow into a very dynamic and natural-looking aquascape that rivals even the best of reef tanks.

When it comes to creatures, macroalgae tanks can house some of the oddballs or lesser kept fish and invertebrates. They provide a great environment for all kinds of unique crustaceans, small fish, and even seahorses; many of the animals that pose a challenge in your classic reef tank for a variety of reasons. 

  • PomPom and other crabs
  • Purple or Flaming Reef Lobster
  • Mantis Shrimp
  • Seahorses & Pipefish
  • Sea Anemone and Anemone Shrimp
  • Goby and Pistol Shrimp
  • Clams, Sponges, or Sea Squirts
  • Feather Dusters
  • Octopus or Cuttlefish
  • Sea Stars

The options really are expansive and limiting yourself to focusing on macroalgae combined with a specific/unique creature is a fun way to engage with the tank. Of course, we always recommend substantial research before diving into a new pet to be sure you are ready, but macroalgae itself is really not all that demanding and provides the perfect playground for something new and challenging.

Being that most macroalgae are fairly hardy and easy to maintain, a tank dedicated to macros can be really affordable. There is no minimum tank size and the algae itself filters the water, just like a refugium. Algae is photosynthetic and removes nutrients from the water as it grows. That means proper lighting is important but you can use very rudimentary filtration and flow techniques without much investment. Many of you just might have everything you need to set up a macroalgae tank sitting in your garage or storage closet from tanks past.