Hammer & Frogspawn Coral Care Guide (Euphyllia)
Hammer coral and Frogspawn coral are two of the most popular large-polyp stony (LPS) corals in the hobby — and for good reason. They belong to the same genus, Euphyllia, share almost identical care, and reward you with fleshy, flowing polyps that pulse and sway in the current like an underwater meadow. Their hardiness and forgiving nature make them an ideal first LPS, while their color range keeps them a favorite of advanced reefers. This guide covers placement, lighting, flow, water chemistry, feeding, aggression, and a complete acclimation routine so your new coral settles in and thrives.
Because Hammer and Frogspawn are the same genus with the same requirements, we’ve combined them into one care guide. Where they differ — mostly in polyp shape and a note on aggression — we call it out below.
Hammer vs. Frogspawn vs. Torch: Telling Euphyllia Apart
All three are Euphyllia and are cared for the same way. The difference is in the tip of the polyp and the skeleton structure:
- Hammer coral (Euphyllia ancora/paraancora): polyp tips are shaped like a hammer, anchor, or T. Available as branching or wall (single skeleton) forms.
- Frogspawn coral (Euphyllia divisa/yaeyamaensis): polyp tips are rounded and grape-like, giving a bushy, “fish eggs” look that never fully retracts, adding constant motion.
- Torch coral (Euphyllia glabrescens): long, flowing tentacles tipped with a rounded knob, extending from tube-shaped corallites. Torches are the most aggressive of the three.
Care Level: Great for Beginners
Euphyllia are considered easy-to-moderate LPS. They are hardier than SPS and more forgiving than many other LPS, tolerating minor swings while you dial in your tank. The most common mistakes are too much flow, too much light, and placing them where they can sting — or be stung by — a neighbor. Get those three right and Euphyllia are close to bulletproof.
Quick-Reference Care Parameters
| Coral type | LPS (Large Polyp Stony) |
| Care level | Beginner–Intermediate |
| Lighting | Low–Moderate · PAR 50–150 (sweet spot ~75–125) |
| Flow | Low–Moderate, indirect and random |
| Placement | Middle to lower third of the tank |
| Temperature | 76–82°F (ideal ~78°F) |
| Salinity | 1.024–1.026 (~35 ppt) |
| Alkalinity | 8–11 dKH |
| Calcium | 400–450 ppm |
| Magnesium | 1250–1350 ppm |
| Nitrate | 2–10 ppm (they like a little food in the water) |
| Phosphate | 0.03–0.10 ppm |
| Feeding | Optional · meaty foods 1–2× per week |
| Aggression | High · long sweeper tentacles · give 4–6+ inches of space |
Lighting
Euphyllia are photosynthetic — they host symbiotic zooxanthellae that feed them through light — but they do not want intense light. Low-to-moderate output in the PAR 50–150 range is ideal, with most hobbyists finding the sweet spot around 75–125 PAR. Too much light bleaches the tissue and washes out color; too little starves the coral and leads to poor polyp extension. If you run high-output LEDs, keep Euphyllia lower in the tank or in a shaded spot, and let them adjust to your lighting gradually over one to two weeks.
Water Flow
Aim for low-to-moderate, indirect flow. You want the polyps to sway gently, not whip or fold over on themselves. Direct, high-velocity flow keeps the polyps deflated and can tear the delicate flesh over time; too little flow lets detritus settle on the coral. Random, turbulent flow from a wavemaker — rather than a laminar jet pointed straight at the coral — produces the best, fullest polyp extension.
Placement & Spacing (Very Important)
Place Euphyllia in the middle to lower third of the tank where light and flow are moderate. The single most important rule with these corals is spacing: Hammer, Frogspawn, and especially Torch extend long sweeper tentacles at night that are packed with stinging cells. They will damage or kill any non-Euphyllia coral they can reach.
- Give at least 4–6 inches of open space between a Euphyllia and any other coral (more for large colonies and Torches).
- Euphyllia species generally tolerate each other, so you can group Hammers, Frogspawns, and Torches into a “Euphyllia garden” — but still leave a little breathing room, as Torches can sting Hammers and Frogspawns.
- Secure the frag plug or skeleton so the coral can’t topple or roll onto a neighbor. Handle by the skeleton or plug only — never squeeze the fleshy polyps.
Water Parameters
Like all stony corals, Euphyllia build a calcium-carbonate skeleton, so stable alkalinity, calcium, and magnesium matter. What they care about most, though, is stability — a steady 8 dKH beats an 11 dKH that swings. Target 8–11 dKH alkalinity, 400–450 ppm calcium, and 1250–1350 ppm magnesium. Keep temperature and salinity rock-steady (78°F, 1.025). Unlike ultra-low-nutrient SPS systems, Euphyllia actually color up better with a little nutrient in the water — nitrate around 2–10 ppm and phosphate around 0.03–0.10 ppm is a healthy target.
Feeding
Euphyllia get most of their energy from light, so feeding is optional but beneficial for faster growth and better color. Once or twice a week, target-feed the extended polyps with small meaty foods — mysis shrimp, chopped brine, or a reef pellet/coral food. Feed when the tentacles are out (often after lights-out or when a little food is in the water), gently release food over the polyps, and avoid overfeeding the tank. Do not feed a coral that is closed up or clearly stressed; wait until it’s open and settled.
Common Problems & How to Fix Them
- Not opening / poor extension: usually too much flow or light, a parameter swing, or normal new-tank stress. Move the coral lower, reduce direct flow, and confirm your parameters are stable. Give it a few days before reacting.
- Brown jelly disease: a fast-spreading brown, mucousy film that melts tissue. Act immediately — remove the coral, dip it, cut away any affected flesh in a separate container, rinse, and re-dip before returning it. Improve flow and stability to prevent it.
- Recession / receding tissue from the skeleton: a sign of stress from swings in alkalinity, temperature, or salinity, or from a nearby stinging coral. Fix the underlying instability and check spacing.
- Polyp “bail-out”: under severe stress, Euphyllia can eject polyps that may re-attach elsewhere. Prevention is stability — avoid big, sudden changes.
How to Acclimate Your New Hammer or Frogspawn Coral
Euphyllia are shipped retracted — this is normal transit stress and they typically re-inflate within hours to a few days. A calm, gradual acclimation is the key to a smooth transition. Here is the routine we recommend:
- Temperature match (15–20 min): With aquarium lights off or dimmed, float the sealed bag in your tank (or sump) to bring the water temperature together gently.
- Drip acclimate (30–45+ min): Open the bag into a clean container and set up a slow drip line from the tank (2–4 drips per second). Euphyllia are sensitive to sudden shifts in salinity and pH, so take your time until the container volume has roughly doubled.
- Coral dip (5–10 min): Dip in a reef-safe coral dip (such as Coral Rx or a Bayer-based dip) per the product directions to remove hitchhiking pests, then rinse in clean saltwater. Be gentle — swirl rather than blast the delicate flesh.
- Placement: Start the coral low in the tank in a lower-light, gentle-flow spot — never immediately under bright lights. Make sure it isn’t within sweeper range of any neighbor.
- Let it settle: Leave the coral alone for the first several days. Keep lights on the dimmer side at first and slowly raise intensity (or move the coral up) over one to two weeks. Don’t panic if the polyps stay closed for a day or three — that’s normal.
Handling tip: always hold the coral by its skeleton or frag plug. The fleshy polyps are easily bruised, and squeezing them can cause damage that invites infection.
Frequently Asked Questions
Are Hammer and Frogspawn corals good for beginners?
Yes. They’re among the easiest LPS corals to keep — hardy, forgiving, and readily available. Nail down moderate light, gentle flow, and good spacing and they’re a fantastic first stony coral.
Why won’t my Hammer or Frogspawn open up?
The usual culprits are too much flow, too much light, an unstable parameter (alkalinity or salinity), or simple new-coral stress. Move it lower, soften the flow hitting it, confirm stability, and give it time.
Can I keep Hammer, Frogspawn, and Torch together?
Euphyllia species generally tolerate one another, so a Euphyllia garden works well. Still leave a little space — Torch coral is the most aggressive and can sting Hammers and Frogspawns it contacts.
How often should I feed them?
Feeding is optional. Once or twice a week with small meaty foods will boost growth and color, but a healthy Euphyllia under good light will do fine on light alone.
What is WYSIWYG coral?
WYSIWYG means “What You See Is What You Get.” The exact coral in the photo is the one that ships to you — no surprises on color, size, or pattern.
Shop WYSIWYG Hammer & Frogspawn Coral
Every Euphyllia we offer is a hand-selected, photographed WYSIWYG specimen. Browse our current live coral for sale to see this week’s Hammers, Frogspawns, and Torches, and pair your new coral with a healthy, stable reef using our lighting, flow, and dosing equipment.
New to reef keeping or expanding your collection? Explore our other care guides, including the Goniopora (Flowerpot) Coral Care Guide and the Cynarina Coral Care Guide.
