Bubble Tip and Rock Flower Anemone Care Guide

The bubble tip you added on Saturday is on the other side of the tank by Tuesday, and its foot is an inch from a powerhead. That is the first lesson most people learn about anemones. The second is that the two you’re most likely to buy, the bubble tip and the rock flower, are very different animals.

This guide covers both: which one fits your tank, light, flow, water, feeding, clownfish, what a healthy anemone looks like, and how to keep one from walking into trouble.

Two anemones, two different animals

	Bubble tip (Entacmaea quadricolor)	Rock flower (Phymanthus crucifer)
Home	Indo-Pacific reefs, including the Red Sea	Florida and the Caribbean
Size	Up to about 12 inches, usually smaller in bright tanks	Up to about 6 inches, most 3 to 4
Light	Moderate to high	Moderate
Wanders	Often, until it finds a spot it likes	Rarely
Hosts clownfish	Yes, more species than any other anemone	No
Sting	Strong, with a long reach	Weaker, short reach
Beginner fit	Best first anemone for a mature tank	One of the easiest anemones in the hobby

A note on names: rock flowers are still sold as Epicystis crucifer, but the World Register of Marine Species now lists the accepted name as Phymanthus crucifer. Same animal.

When to add one

For a bubble tip, the common advice is a tank that has been running and stable for at least six months, and at least 30 gallons. That rule comes from farms and experienced keepers, not a study, but it holds up for a simple reason: an anemone that is unhappy with your water goes looking for better water. Jeff Kurtz recommends adding a bubble tip before other invertebrates and letting it settle, and Jeremy Gay places his before the corals go in, so it picks its spot before there is anything to sting.

Rock flowers are more forgiving. Kurtz calls them “very hardy” and a good choice “even for beginners,” and no source puts a tank-age minimum on them.

33 gallons, just over the 30-gallon minimum.

Light

Bubble tips run on light. Most of their energy comes from the algae living in their tissue, and without enough light they bleach. Vendors put them anywhere from about 150 to 350 PAR. Start lower and raise it slowly over a few weeks. A bubble tip that stretches out thin and “stringy” is usually asking for more light or more food.

The bubbles themselves come mostly from light. J. Charles Delbeek at the Waikiki Aquarium tracked their exhibit: under reduced indoor light the anemones lost their bulbs, and once they were moved outside into full, long sun almost all of them grew bubble tips. Bubbles are not a proven sign of health, so don’t panic if yours has none.

Rock flowers want less. Top Shelf Aquatics suggests 80 to 150 PAR, and warns that a sudden jump in light can bleach them.

Bubble tips want about 150 to 350 PAR. A meter tells you where yours is.

Placement, wandering and pump guards

A new bubble tip will move around for the first few weeks while it looks for a spot with the light and flow it wants. That’s normal. Constant wandering after that usually points to a problem with water or light. Jeremy Gay’s trick is to hold the anemone over the spot you want for about 10 minutes so its foot can grab on.

Cover every powerhead, pump intake and overflow before a bubble tip goes in. Reef Builders puts it bluntly: the spinning blades have to be covered “to prevent the anemone from wandering into a deadly situation.” A wandering anemone that gets pulled into a pump dies, and it can take the rest of the tank’s water quality with it.

Rock flowers like the bottom. In the wild they sit in sand with the foot anchored to rock underneath, so in a tank they settle at the base of the rockwork with the foot down in the sand. Once a rock flower finds a spot with good light, it usually stays there.

Cover every pump intake before an anemone goes in.

Flow

Bubble tips like medium, turbulent flow, not a direct blast. Rock flowers want it gentler: moderate and indirect. Too much flow can peel a rock flower off the rock and send it floating. When you first add one, turn the flow down so the foot can attach.

Water

Parameter	Target
Temperature	76 to 78°F, held steady
Salinity	1.025 to 1.026
pH	8.1 to 8.4
Alkalinity	8 to 12 dKH, held steady
Calcium	400 to 450 ppm
Magnesium	1300 to 1400 ppm

Temperature is the one to watch, especially in summer. In a 2014 study, bubble tips held at about 83°F for six weeks bleached, and their algae still hadn’t recovered months later. In the wild, a 2016 heat wave bleached every bubble tip surveyed at Lizard Island on the Great Barrier Reef, and most were gone by October. Rapid temperature changes also bleach anemones, so keep swings small.

No source gives nitrate or phosphate targets specific to either anemone. The stable reef water your corals like works for them too.

Temperature is the one to watch: a thermometer, and a combined chiller and heater for summer.

Feeding

Bubble tips grow better fed, and this one has real evidence behind it. In a 2014 study of bubble tips that had been cut in half or quarters, feeding increased oral disc growth and reduced weight loss. A Red Sea field study found bubble tips living with large clownfish survived and grew over several years, while those with no fish shrank and eventually disappeared.

Keep it to small, meaty food: mysis, chopped shrimp or fish, or anemone pellets. Kurtz fed his every three to four days, and Top Shelf suggests two to three times a week. Overfeeding fouls the water, so remove anything it spits out. How it takes food is also your best health check. LiveAquaria calls the feeding response “very important” in judging an anemone.

Rock flowers need less. Light is their main food, and one or two small feedings of mysis or brine shrimp a week, basted onto the tentacles, speeds growth.

Clownfish

The bubble tip hosts more clownfish species than any other anemone, and for the maroon clownfish it’s the only natural host. The common ocellaris clownfish is a different story. In the wild it lives in other anemones, but in aquariums it often moves into a bubble tip. Often, not always. Some clowns take to one quickly, and some never do. Hosting clowns can also turn aggressive defending their anemone.

Rock flowers don’t host clownfish. The two never meet in the wild, since clownfish live only in the Indian and Pacific Oceans and rock flowers are Atlantic animals. A clownfish that keeps pestering a rock flower can stress it. Rock flowers do sometimes host small shrimp and porcelain crabs.

Healthy or stressed

A healthy anemone is inflated, firmly attached, has its mouth closed, and grabs food. Anemones deflate now and then, and a short deflation is normal. Watch for:

• A mouth gaping wide enough to see inside
• Deflated for a long stretch, or a foot that won’t attach
• White, pale or see-through color, which is bleaching
• Not holding onto food

Check temperature first, then light and flow. An anemone that is falling apart should come out of the tank right away, followed by a water change, since a decaying anemone fouls water fast. After shipping, though, give a limp new arrival a chance. LiveAquaria says to “always follow the acclimation procedure even if your new arrival appears to be dead.”

Splitting

Bubble tips clone themselves by splitting in two. At the Waikiki Aquarium, splitting produced more than 20 bubble tips over eight years. They can also be cut: in the 2014 study, about 90% of halves survived. Cutting is a job for experienced keepers.

Rock flowers rarely split. They reproduce by spawning, and keepers with a group sometimes find babies turning up on the sand.

Anemones and corals

A bubble tip carries a strong sting and walks, so it will sting any coral it wanders into. Place it first, give it room, and wear gloves when you handle one. Rock flowers have a weaker sting and a short reach, and they mostly stay put, so they’re easier around corals. They still sting what they touch.

Acclimation and dipping

Anemones are more sensitive to salinity changes than fish. LiveAquaria keeps acclimation to an hour or less and leaves the tank lights off for at least four hours after. Bring the light up gradually from there.

Most farms don’t dip anemones. World Wide Corals says not to dip rock flowers because it can harm them, and Reef Builders doesn’t recommend dipping a bubble tip on arrival either. Inspect it closely instead, and quarantine it if you can. If you do dip, use a product labeled safe for anemones and follow the label exactly.

A Florida anemone

The rock flower is a local. It lives in the Florida Keys, Biscayne Bay and across the Caribbean, usually buried in sand near the reef with only its disc showing. In Florida, the Fish and Wildlife Conservation Commission regulates it as marine life, with bag and possession limits for collectors. The only anemone Florida bans outright is the giant Caribbean anemone.

Quick answers

Do bubble tip anemones move?

Yes, especially in the first few weeks. Cover pumps and overflows before you add one.

Do rock flower anemones host clownfish?

No. They come from different oceans.

Why isn’t my bubble tip bubbly?

Usually light. Bubbles showed up at the Waikiki Aquarium under strong, long sunlight. A bubble tip without bubbles can still be healthy.

Which anemone is best for a beginner?

The rock flower. If you want a clownfish host, a bubble tip in a mature, stable tank.

Sources

• J. Charles Delbeek, lighting and bulb tips in Entacmaea quadricolor, Advanced Aquarist (2002)
• Scott, Hardefeldt and Hall (2014), asexual propagation of Entacmaea quadricolor, PLOS ONE
• Porat and Chadwick-Furman (2004), effects of anemonefish on giant sea anemones, Hydrobiologia
• Hill et al. (2014), bleaching in Entacmaea quadricolor, Marine Biology
• Jeff Kurtz, Reef Builders: adding bubble tips to a stocked reef and the flower anemone (2020)
• LiveAquaria, quarantine procedures for anemones
• Florida Fish and Wildlife Conservation Commission, recreational marine life regulations

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.