Hammer Coral: Wall vs Branching, Care and WYSIWYG Hammers for Sale

Hammer corals get their name from the tentacle tips, which flatten into a T or anvil shape instead of ending in a knob. That hammer head is the identification — if the tips are rounded you have a torch, and if they branch you have a frogspawn. Under actinic light a wall of moving hammer heads is one of the best displays in the hobby, which is why they anchor so many LPS-dominant tanks.

Two skeletal forms sell under the same name, and the difference decides whether the piece is ever divisible. Euphyllia ancora — the wall hammer — grows as a continuous meandering ridge and cannot be divided without cutting through living tissue. Euphyllia paraancora — the branching hammer — puts each head on its own stalk and frags cleanly. Ask which one you are buying. Our WYSIWYG listings say.

Care at a glance

The early warning most people miss

Hammers shed tissue from the base upward when they run short on energy. The symbionts live in the tentacles and oral region, not the body wall, so the base is the part that costs the animal the most and returns the least. Bare skeleton climbing from the bottom while the tentacles above still look fully inflated is an early warning, not a late one. If you are seeing it, read Hammer coral losing heads: what it means and what to do before you move anything.

How much space a hammer actually needs

The tentacles you see during the day are not the reach. After the lights go down a hammer puts out sweepers — thin, extended feeding tentacles that hunt for whatever is next to it. They carry the stinging cells, and they will find a neighbor you thought was clear.

Leave a hand’s width around every hammer. Less than that and you are relying on the coral being polite, which it is not. The animal that loses this fight is almost never the hammer, so the damage shows up on the acan or the chalice you put beside it and you spend a week wondering what went wrong with that piece instead.

Wall hammers need more room than branching hammers, because the whole ridge is one animal and the sweepers come off the entire perimeter. If you are tight on rock, buy the branching form and give it a corner.

Brown jelly, and why it moves so fast

Euphyllia are the genus people lose to brown jelly, and it is worth knowing what it is before you are looking at it at eleven at night. It is not a disease the coral catches out of nowhere. It is what happens after tissue is already damaged — a fragging cut, a sweeper burn, a fall off the rock, a bad shipping ride — when opportunistic organisms move into the wound. What you see is a loose brown film sitting over receding tissue, and it will strip a colony head by head in a day or two.

Speed matters more than method. Get the coral out, blow the jelly off with a turkey baster of tank water so you can see the actual tissue line, and remove what is already gone. On a branching hammer that means snapping off the affected heads below the damage and keeping the clean ones. On a wall hammer you are cutting into a continuous skeleton, which is why wall colonies are the ones that get lost.

What does not work: waiting to see if it stops, and putting the colony straight back into low flow. Jelly sits where water does not move. Come back with more flow across the piece than you had before, not less.

What to look at before you buy one

Count the heads and then look underneath them. On a branching hammer, every head should sit on its own solid stalk with no bare or dark skeleton at the junction. That junction is where a struggling colony gives up first, and a photo taken from directly above will hide it completely.

Then judge the inflation. A hammer that is happy holds its tentacles out full and slightly loose in the current. One that is holding them in tight, or that looks deflated on one side of the colony, is telling you something about the water it is sitting in right now — and whatever that is, it travels with the animal.

Ask how long the seller has had it and whether it has eaten. A hammer that has been open and feeding in one system for a few weeks is a different purchase from one that landed on a transship pallet on Tuesday, even when the photo looks the same. Ours are conditioned in our Key West systems before they ship, and the photo on a WYSIWYG listing is the exact animal that ships.

Hammers in stock now

Aquacultured in Key West, photographed individually — the photo is the exact animal that ships.

One thing to know before you order: the $10 Box & Handling Fee is charged by the box, not by the coral, and UPS Next Day Air is one flat shipping charge per order. A box holds several corals for the same $10 Box & Handling Fee and the same overnight ride, Florida orders under 6 lb ship UPS Next Day Air for a flat $30, and livestock orders of $349 or more ship free. If this page puts one coral on your list, it is worth seeing what else belongs in the box — start with corals under $100 or the newest WYSIWYG pieces.

Our stony corals are either aquacultured at the shop in Key West under Florida Aquaculture Certificate #AQ0254072 or conditioned in our Key West systems before they ship, and the photo on a WYSIWYG listing is the exact animal that ships. Corals ship UPS Next Day Air every Tuesday and Wednesday. If you are ever in Key West, come see the raceways.