Leptastrea Coral Care: Feeding, Light and Named Morphs

Look at a leptastrea at noon and it is a flat crust of small cups. Look again an hour after the lights go off and the whole colony has gone fuzzy with tentacles, reaching for anything drifting past. That night shift is the key to keeping it. This is a small coral with a big appetite.

Leptastrea is an encrusting stony coral from the Indo-Pacific. It spreads across rock as a low mat of tightly packed cups, and over years it can build up into a mound. It is hardy and easy to light. What separates a leptastrea that just survives from one that spreads and colors up is feeding and spacing.

What leptastrea is

For a long time leptastrea was filed with the favias in the family Faviidae, which is why you still see it sold next to favia and favites, and why some care sheets treat it like a brain coral. In 2012 a DNA-based revision by Budd and colleagues showed that Faviidae was a mixed group with no single common ancestor. Leptastrea was pulled out and left with no family for years. The World Register of Marine Species now lists it in its own family, Leptastreidae.

It is sold as LPS, and we list it with our LPS corals, even though the polyps are small. In care terms it sits between the two: lit like a medium-light stony coral, fed like an LPS.

The wild animal is plainer than the frags you see in stores. A CORAL Magazine article on Leptastrea purpurea in Guam describes wild colonies there as mostly brown, yellowish or ocher, while aquarium colonies in the US come in gold, purple, vivid green and orange. The bright morphs are the result of hobbyists picking out the best colors and fragging them.

Feeding: it eats more than it looks

Leptastrea gets part of its energy from the algae in its tissue, but it is a real predator at night. The same CORAL Magazine article notes that the corals start catching prey at dusk. Researchers there feed their broodstock live baby brine shrimp overnight, and when night feeding falls short, the corals produce fewer larvae for weeks until good food comes back. Growers who culture leptastrea report the same thing in plainer terms: regular target feeding makes it grow faster.

• Feed small zooplankton foods such as rotifers, copepods, cyclops or a reef powder. It will also take the odd piece of mysis.
• Feed 30 to 60 minutes after the lights go off, when the tentacles are already out.
• Two or three times a week is plenty.
• Turn the pumps down for about 30 minutes and puff the food gently over the colony with a pipette.

Do not overdo it. Uneaten food rots in the rock and feeds algae, and algae will smother a low encrusting coral faster than it smothers a tall one. Our coral feeding guide goes deeper on target feeding.

Light and flow numbers

Our listings run leptastrea at medium light, 100 to 200 PAR, with medium, indirect flow. Growers who culture a lot of it settle most colonies around 100 PAR and say green morphs handle a little more light than orange ones. Too much light makes the polyps stay pulled in. Too little and the colors fade, and some green morphs turn brown. If you are unsure, start low and raise it over a few weeks. That is the safer mistake.

Flow should be enough to keep detritus off the cups without blasting them. Changing, indirect flow from a modern pump works well. Flow that hits one side constantly keeps the tissue drawn tight against the skeleton. Leptastrea also does well in the lower part of the tank, a zone that is often hard to fill.

Sweepers and spacing

Leptastrea is not a hydnophora or a galaxea. It has short sweeper tentacles at night with a mild sting, and like any encruster it will fight whatever it grows into. Our Full Moon listing says to leave a little space, and growers commonly suggest 1 to 2 inches. Keep it well away from corals with long sweepers, like euphyllia (torch, hammer, frogspawn), galaxea and hydnophora. Those will win.

Check spacing at night with a flashlight. The colony is bigger in the dark than it is at noon.

Named morphs

Leptastrea morphs are fragged and named, and the names usually hint at the colors.

Morph	What the name refers to
John Deere	Green and yellow, like the tractor company’s colors. One of the best known leptastrea names in the hobby.
Full Moon	Bright green polyp centers scattered across a dark encrusting base.
Other names in the trade	Spit Fire, Ice Blue, Burning Ember and Goblin are a few you may see elsewhere.

Color shifts with lighting, so a morph can look a little different in your tank than in the photo. A trade name is a color selection, not a species.

Growth: patient, then steady

A frag encrusts over its cut edge and plug first, then spreads thinly onto the rock around it. Over time it thickens into a low mound. Feeding speeds this up. Coral grown from larvae is much slower: in the Guam research, colonies raised from larvae in aquariums were only about an inch across after three years. A frag is already a head start on that.

Leave room for it to spread, and do not leave it sitting on a frag rack or egg crate for months. It will grow onto the rack.

Things you probably did not know

• Leptastrea purpurea keeps both sexes in the same polyps and broods its young. In the Guam study it released larvae every day, where many reef corals spawn once a year in a single mass event.
• Those larvae glow green under blue light because they are full of green fluorescent protein.
• In Guam it lives on shallow reef flats that reach about 93°F at a midday low tide, and in tide pools that get even hotter. The researcher calls it a pioneer species.
• In Hong Kong, tube worms often bore into it, and the coral grows up around them into little horns.

Common problems

What you see	Likely cause	What to do
Polyps stay pulled in, tissue tight	Too much light, or flow hitting one side	Lower it or dim the light, soften and vary the flow
Faded color, or green turning brown	Too little light	Raise it gradually
Slow or no growth	Not enough food, or nitrate near zero	Target feed at night, keep some nitrate. See the water parameters guide
Tissue receding from the edge	A neighbor’s sweepers, nutrient trouble or alkalinity swings	Check spacing at night, then test. See bleaching vs STN vs RTN
Algae creeping over the cups	Overfeeding or low flow	Feed less, add flow, pick off what you can

Fragging

The easy way is to set a plug against the growing edge and let the colony encrust onto it, then cut it free. You can also cut a clean piece with a saw and glue it to a plug. Many leptastrea frags are lost because the piece never attaches, so use enough glue to seat it firmly and keep it out of strong flow until it grips. Wear gloves when you cut.

Acclimation

Corals do not need a drip. Turn the lights off and float the sealed bag for 15 to 20 minutes. Open it into a clean container and add about half a cup of tank water every few minutes for 15 to 30 minutes. Lift the coral out by its plug and throw the bag water away. Dip it before it goes in the display, then place it low in the tank with the light off or low for the first day.

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