Brain Coral Care: Trachyphyllia, Lobophyllia, Symphyllia and Wilsoni

By day an open brain is a puffy, glowing mound on the sand. After the lights go out it turns into something else: rows of sticky tentacles reach out from the mouths, feeling the water for food. Drop a piece of mysis near it after dark and watch it disappear.

This guide covers the fleshy brain corals most reef shops sell: Trachyphyllia, Lobophyllia, the corals still sold as Symphyllia, and the Western Australian wilsoni. Their care overlaps a lot. Where they differ is where they sit in the tank and how much they want to be fed.

Which brain coral is which

The names are a mess, so start here.

• Trachyphyllia, the open brain, lives loose on the sand with no rock base. It is usually shaped like a figure eight, with one to three mouths. Pieces sold as “Wellsophyllia” are a rounder growth form; coral author James Fatherree considers it the same species, Trachyphyllia geoffroyi.
• Lobophyllia, the lobo, grows attached to reef rock, often as separate rounded heads on branches.
• Symphyllia no longer exists as a genus. A 2016 genetic study by Huang and colleagues moved every Symphyllia, along with Australomussa, into Lobophyllia. The old name still sells, including on our own listings, but these are lobos with long connected valleys instead of separate heads.
• Wilsoni, the old Symphyllia wilsoni, went its own way in 2016 as Australophyllia wilsoni. It comes only from Western Australia and is known for bright, busy color.

Despite the shared nickname, the open brain isn’t closely related to the lobos. Genetic work puts Trachyphyllia in the family Merulinidae, closer to favias, while the lobos and wilsoni sit in Lobophylliidae. None of them is the brain coral Florida divers see on our reefs. These are all Indo-Pacific corals.

An open brain (Trachyphyllia), a lobo (Lobophyllia) and a Wilsoni (Australophyllia wilsoni), all from our listings.

Where to put it

This is the real difference between them, and it comes from where they live in the wild.

Open brains come from soft bottoms: sand and mud between reefs, often around 100 feet deep according to Fatherree. Put a trachy loose on the sand bed with open space all around so the flesh can fully expand. Don’t wedge it into rock. Keep sand-sifting gobies, pistol shrimp and burrowing wrasses away from it, since they can bury it.

Lobos, the former Symphyllia and wilsoni grow on reef slopes. Set them low in the tank on a flat, stable rock or on the sand bed. Tidal Gardens adds a practical rule: make sure nothing can fall on it and it can’t fall. Falls tear the flesh, and those injuries heal poorly.

Give every one of them room. They put out sweeper tentacles at night, and lobos can push out digestive filaments after dark to attack neighbors. Vendors suggest anywhere from 2 to 8 inches of clearance. Four inches is a reasonable start, with more space for a large colony.

Open brains sit loose on the sand. Lobos grow attached to rock.

Light and flow

These corals don’t want much light. Tidal Gardens keeps open brains at 50 to 100 PAR and says lobos usually don’t need more than 100. Most other farms land between 50 and 150. Start a new piece at the low end and raise it slowly over a few weeks, because light shock is a bigger risk than too little light. Fatherree also debunks an old rule: green open brains don’t need bright light while red ones need dim light. Both do fine under the same lighting.

Flow should be low to moderate and indirect, enough to carry waste away from the mouths and no more. Strong flow does real damage here. The flesh is a thin, fleshy layer over a skeleton with sharp ridges and teeth. Blast it with a powerhead and the tissue gets pushed onto those edges and cuts itself, then recedes.

Water

No source gives chemistry specific to these corals. The farms use the same targets for all of them, and stability matters more than any single number.

Parameter	Target
Temperature	76 to 80°F
Salinity	1.025 to 1.026
Alkalinity	8 to 9 dKH
Calcium	400 to 450 ppm
Magnesium	1300 to 1350 ppm
Nitrate	5 to 10 ppm
Phosphate	0.05 to 0.1 ppm

Nutrients cut both ways. Tidal Gardens says near-zero nutrients give an open brain a shrunken, starved look, while high nutrients dull the color, and lobos can start receding once nitrate climbs to 30 or 40 ppm.

Feeding at night

All of these corals feed after dark. The feeder tentacles come out in the evening, and an open brain’s mouth changes from a slit to what Fatherree describes as puckered lips when it smells food. That is the time to feed.

What works is small, meaty food: mysis, brine shrimp, chopped krill or clam, and LPS pellets. Turn the pumps off for about 10 minutes, place the food on the mouths with a baster or feeding tube, and keep an eye on shrimp and fish that will steal it.

How often depends on which coral it is. Open brain sources lean toward feeding one to three times a week. Lobo sources lean the other way. Tidal Gardens calls lobos such active feeders that they don’t need much spot feeding, and Reef Builders says Lobophyllia robusta can go months without target feeding. Tidal Gardens says wilsoni grows noticeably faster with regular feeding.

No one has run a feeding trial on these corals, so every schedule you read, this one included, comes from farm and hobby experience. The broader science supports feeding in general: a 2009 review found that food supplies 15 to 35% of a healthy coral’s daily needs, plus nitrogen and phosphorus that light can’t provide. Our guide to spot feeding corals covers the technique.

Small, meaty food and a target feeder for feeding after lights out.

Common problems

What you see	Likely cause	What to do
Won’t inflate	Stress from shipping, light, flow or an alkalinity swing	Test alkalinity, lower the flow, give it time in lower light
Flesh pulling back, skeleton showing	Strong flow, a fall, a sting, or high nitrate	Move it to calmer water on flat sand or rock and check nitrate
Brown, slimy jelly on the flesh	Brown jelly, caused by ciliates	Pull it out, siphon off the jelly, cut back to healthy tissue, dip and isolate
Closed up with good water	A fish picking at it at night	Watch after lights out; dwarf angels are the usual suspects
Losing color fast	Too much light	Lower it or dim the light

Brown jelly moves fast. In a 2022 study, one ciliate killed every infected coral in the study within 72 hours, though the corals tested didn’t include brain corals. Act the same day you see it.

On fish: Reef Builders calls the lemonpeel angel “probably the worst” dwarf angel for nipping LPS, and bicolor, cherub, Potter’s and golden angels can do it too. Some individual wrasses pick at brain corals, but most reef-safe wrasses leave them alone.

Also check the underside. Flatworms like to hide under open brains, and a dip or a gentle squirt of water clears them.

After shipping: go slow

A new brain coral has just been squeezed, bagged and bounced across the country, and shipping damage is one of the main causes of recession later on. Float the bag to match temperature, move the coral into a container of tank water, and gently baste off any mucus. Pick it up by the skeleton or rock base, never by the flesh.

World Wide Corals waits 10 to 24 hours after a new coral goes in before dipping it, which is gentler on a stressed piece. When you dip, follow the label exactly. Fleshy corals pull in when dipped, so pests can hide in the folds, and Bulk Reef Supply notes they may need more than one dip. Start it low in the tank and bring the light up over one to two weeks.

Is a brain coral a good beginner coral?

An open brain can be. Fatherree calls them “categorically some of the hardiest corals you can choose from,” and Jeff Kurtz considers them a good early LPS. Lobos get more mixed ratings, from easy to more challenging than most LPS, so they fit better as a second LPS. Wilsoni is a showpiece for a stable tank.

The real beginner risk isn’t the daily care. It’s starting with a damaged coral. When you buy one, look for puffy, fully inflated flesh and a closed mouth, and pass on a piece with pinched tissue, a gaping mouth or bare skeleton. That is why we sell most of our brain corals as WYSIWYG: the photo is the coral you get.

Quick answers

Do brain corals sting?

Yes. They put out sweeper tentacles at night, and lobos can attack neighbors with digestive filaments. They also lose to stronger corals, so open space protects them both ways.

How fast do brain corals grow?

Slowly. Tidal Gardens calls open brains somewhat slow growers, and Reef Builders calls Lobophyllia robusta very slow. Regular feeding helps.

Trachyphyllia or Lobophyllia?

If it sits loose on the sand with no rock base, it’s an open brain. If it’s attached to rock, it’s a lobo, including anything sold as Symphyllia.

Sources

• James Fatherree, a look at Trachyphyllia geoffroyi, Reefs.com
• Huang et al. (2016), taxonomy of Lobophylliidae, Zoological Journal of the Linnean Society
• Jeff Kurtz (2013), beginner LPS: the open brain, Reef Builders
• Houlbreque and Ferrier-Pages (2009), heterotrophy in tropical corals, Biological Reviews
• Tidal Gardens, Trachyphyllia care, Lobophyllia care and Australophyllia care
• Reef Builders, FAQs on dwarf angelfish (2023)

The Underwater Gardener grows aquacultured corals in Key West, Florida (FL Aquaculture Certificate #AQ0254072). Our corals are raised under stable reef lighting in our own systems, so they arrive already adapted to a well-run tank. Corals ship UPS Next Day Air every Tuesday and Wednesday.