Hey, Reefers! Let’s talk Acropora!
If an everyday, non-reefing individual was told to picture a coral, they are most likely envisioning an Acropora. Acropora, or Acro for short, are the pinnacle of not only reef keeping but actual reefs in the ocean. These reef-building and creating corals are the poster child for corals worldwide! Making them an extremely rewarding addition to any reef tank.
Acros have been one of the pillars of our hobby for decades. They are a stunning grouping of SPS (Small Polyp Stony) corals that keep on getting better as the years go by. Acropora comes to us from several regions, Australia, Indonesia, and most recently, Fiji, which opened up again in early 2024 for export. Not to mention the countless strains of aquacultured Acropora that have been grown for generations by hobbyists, your LFS (Local Fish Stores), and coral suppliers around the globe.
The second-to-none coloration of Acros is what has reef keepers hooked on them! With wild Acros, color, and growth structure can vary by region, but named, aquacultured Acros come in just about every color and color combination you could imagine. It is truly remarkable just how many different colors they make shine!
Being vertical and horizontal, growing SPS corals in the right conditions can help Acropora to really grow! Sprouting out in a twisted, clustered grouping of branches that really stand out in a reef tank. This makes them an even more perfect selection for Aquaculture. All those fast-growing branches are easy to frag off and share across our hobby. Hence, another one of their nicknames is Sticks!
Acropora can be prone to pests such as acro-eating flatworms, red bugs and other flatworms. Visually inspect your acros periodically for tissue recession, white spotting of the tissue, retracted polyps, and color change/loss. There’s usually a reason you will see one of these events, so a watchful eye and a regular dipping schedule are important. If you notice the Acro is turning either brown or a light color, this could be due to improper lighting, not having enough nutrients or some type of stress. If you notice any tissue recession/loss, this could also be due to too much flow, water quality issues, an adjacent coral, or pests.
When it comes to caring for your Acropora, their specific conditions should not be taken lightly. Acros can be extremely sensitive; this is why they are generally considered to be an expert care level coral in our hobby. Consistent and stable tank parameters are essential to keeping them. This is why most hobbyists don’t add Acros until their tank is well-established and stable.
Aim for salinity between 1.025 – 1.026 specific gravity, 76-78 degrees F, Calcium of 400 – 450 ppm, Alkalinity of 8 -10 dKH, Magnesium of 1250 – 1350 ppm as well as the lower end of Nitrates/Phosphates. Don’t chase numbers or perfection, having consistent water parameters while avoiding swings is key! Replenish nutrients often by undertaking water changes weekly of roughly 10-20%. Avoid large water changes that can swing parameters abruptly! Smaller, more frequent water changes are best for all corals, fish, invertebrates, and your tank’s ecosystem as a whole.
Clean water and higher nutrient levels are a fine balance to have success keeping and growing them! Place your Acros in an area of very high light and high flow. The higher flow really helps ensure that nutrients are delivered and removes waste. Randomize the flow to closely mimic their natural conditions on the reef, which also helps detritus to not settle and build upon them. Take a close look at the Acro polyps to see if they are gently swaying in the flow, which is what you’re going for! These corals are typically collected and placed close to the surface (although there are some deeper water species). Blast them with light & flow, and watch them flourish!
