Blasto Coral (Blastomussa sp.): Ultimate Care Guide


Blasto Coral, or Blastomussa Coral, are a great coral choice for beginners and intermediate hobbyists looking to move up from soft coral varieties. Although a large polyp stony coral, they are easier to care for than other species of LPS corals.

Blasto Coral can tolerate some swings of tank water parameters. Like many other corals they need sufficient calcium, magnesium and trace mineral levels in their environment.

This coral, although poisonous, is not very aggressive. Usually placed in isolation from other corals, mainly for its own protection.

In nature they will display red, green and blue coloration. Combined with its easy to care for nature, its stunning coloration makes it a great beginner coral. There are some things you’ll need to know to properly care for this popular LPS coral. Let’s get into the details!

Blasto Coral Care

Blasto Coral are easy to care for and suitable for beginners. Although an LPS, they’re not as picky about water parameters as some other large polyp stony corals. They are sensitive to high light intensity. This species doesn’t live near the surface in nature and your tank environment should duplicate the dimmer lighting intensity they prefer. When subject to excessive lighting this species will either retract their polyps or they will balloon up. Either behavior is a sign you’ll need to reduce tank lighting.

Blastomussa Coral does best in low flow environments. Rapid tank currents will cause them to retract their polyps and refuse to open. Eventually they will die if water flow isn’t reduced.

This beginner friendly coral is forgiving about water parameters. Water temperature should be around 72° – 78° F with a pH from 8.1 to 8.4. Moderately hard water with dKH of 8 – 12 is needed. Crushed coral or aragonite substrate is recommended as this will increase alkalinity and hardness.

Blastomussa Coral will need enough calcium and magnesium for best growth. Aim for calcium concentration of 400 – 450 ppm and magnesium concentration of 1200 – 13500 ppm.

Blasto Coral
Blasto Coral

Trace nutrients are also important, especially strontium. Strontium concentration should be around 8 – 10 ppm. This is a low concentration, but you will need to ensure the environment includes sufficient amounts. This is often important when using RO (reverse osmosis) filtered water.

Host to the symbiotic algae zooxanthellae, Blasto Coral don’t need much in the way of feeding. If you have a healthy tank ecosystem they should be fine. A refugium with a solid community of copepods is a sure sign that your tank ecosystem will support healthy Blastos.

Although optional, you can feed Blasto Coral with a target feeder if you want to encourage growth. Just make sure to offer food to every polyp as each one is a separate organism.

Blasto Coral Placement

Blasto Coral should be placed on live rocks away from other, more aggressive corals. That isn’t to say that this coral isn’t aggressive. Capable of stinging with poisonous sweeper tentacles, it should be placed away from other corals it might harm. However, Blastomussa Coral will often be the looser in any coral fight. Their sting is less potent than some other coral species. Isolating Blastos does more to protect themselves than others.

Low flow areas of your tank are best. Blasto coral doesn’t tolerate high-flow and will retract its polyps if currents are too fast. Place as far from power heads and other sources of current as possible. Also consider using hardscape features to provide current breaks.

Why is my Blasto Coral Dying?

While mostly easy to care for, Blasto Coral can be harmed by too much light, too much current and by insufficient mineral content in its environment. If your Blastomussa Coral is retracting its polyps, consider if you need to reduce your lighting intensity or reduce current flow in your tank. If this coral develops a swollen, inflated appearance this can be an indication of too much light exposure.

Check your water parameters. Ensure there is enough calcium and magnesium present. Calcium concentration should be 400 – 450 ppm and magnesium concentration should be 1200 – 13500 ppm. Micronutrients are required as well. If you are using RO water you will likely need to include trace elements. Blasto Coral especially benefits from strontium, this should have a concentration of 8 – 10 ppm.

Blasto Coral Growth Rate

Blasto Coral grow at a moderately slow rate but this can be increased with feeding. A refugium capable of supporting a strong community of copepods is a good sign you have enough microfauna available to keep your Blastos growing without special feeding.

Blastomussa Coral doesn’t grow fast enough to swamp tanks as do some other corals. This species should be placed on live rock separate from other corals. This is mainly to protect Blastos. As although they are poisonous, Blastos are at a disadvantage to some other corals that have even more powerful stings.

If you want to take extra steps to increase growth you can use a target feeder to apply prepared foods intended for corals such as Reef Chili. Blasto Coral can benefit from other foods such as mysis shrimp and phytoplankton. Feeding frequency should start at every three days to every other day. Adjust schedule as needed for your tank.

When target feeding Blasto Corals turn off all power heads and other sources of flow in your tank. Apply feed directly to each polyp with a target feeder. Every polyp is a separate organism and will need to be fed individually. When they have had enough time to feed, flow can be restored. 30 minutes of no flow is often adequate.

How to Frag Blasto Coral

Blasto Coral can be fragmented, or fragged, by separating polyps with a Dremel hand tool or band saw. Fragging can be used to propagate your corals for sale or trade but proper preparation is needed.

Before deciding to frag, ensure that your corals have grown enough for clear divisions between polyps to appear. Ideally you will want to make cuts without harming any coral flesh. This is not always possible so be ready with a bucket of tank water with the addition of coral tissue supplement such as Brightwell Aquatics Restore. Allowing your fragged corals to soak in this solution will help heal any injuries they suffered during the process.

Before removing from tank water, make sure your Blastos have fully retracted their polyps. Use cuts from multiple directions if needed to carefully separate polyps. Your goal is to find natural separations between polyps and only cut there. This is sometimes easier said than done. Blastos have sensitive flesh that is subject to infections when cut.

Blastomussa Coral Species

Blastomussa Corals are available in a few different species. From the more common Blastomussa wellsi to the smaller polyps of Blastomussa merleti. Some species have been recorded but are unknown in the aquarium hobby. Let’s look at some of these species.

Blastomussa wellsi

Blastomussa wellsi is one of the most common species of Blastomussa available to aquarium hobbyists. Most commonly seen with a red body and teal center starburst, other colors are possible including green and purple. Like other Blastos, B. wellsi has sweeper tentacles but not a very potent sting. It is best to locate this coral separately from others, mainly for its own protection.

Blastomussa merleti

Blastomussa merleti is a common form of Blastomussa that features smaller polyps than its relative B. wellsi. Care requirements are similar to other Blastos. This coral will need correct water parameters including enough calcium and magnesium. Trace micronutrients are also highly recommended, especially strontium.

Blastomussa vivida

Only identified as recently as 2014, Blastomussa vivida will impress as the centerpiece of a marine aquarium. B. vivida features bright and flamboyant coloration in red, purple and green. Matched only by the most impressive specimens of B. wellsi, B. vivida is an impressive coral variety that is sure to become more popular in the coming years.

Blastomussa loyae

Endemic to the Red Sea, Blastomussa loyae features white “spokes,” a dark red oral disc and small bright green tentacles. An impressive species in photographs, we can only hope it will become available to hobbyists in the coming years.

Blastomussa omanensis

First identified in the Arabian Sea in 1991, it is unknown if this species has been successfully kept in captivity.

Blastomussa wellsi vs Blastomussa merleti

Blastomussa wellsi and Blastomussa merleti differ mainly in polyp size. Blastomussa merleti has smaller polyps than B. wellsi. Other than this difference they are otherwise similar and need comparable water parameters and care.

Blasto Coral vs Acan Coral

Though both are easy to care for, Blasto Coral (Blastomussa Wellsi) and Acan Coral (Acanthastrea echinata) differ in temperament and coloration. A. echinata is known for its bright and varied colors. This coral adds an intense multicolored flourish to any reef aquarium. A. echinata is much more aggressive than B. wellsi. During nocturnal feeding A. echinata will fully extend its mesenterial filaments and digest anything within reach. Make sure to place these far from other corals due to its aggressive feeding behavior.

Fish Laboratory

With decades of collective fishkeeping experience, we are happy to share the fish care tips that we've picked up along the way. Our goal at Fish Laboratory is to keep publishing accurate content to help fishkeepers keep their fish and aquarium healthy.

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