Please visit our Sponsors

Related FAQs: Brown Algae, Brown Algae 2, Brown Algae Identification, Brown Algae Behavior, Brown Algae Compatibility/Control, Brown Algae Selection, Brown Algae Systems, Brown Algae Nutrition, Brown Algae Disease, Brown Algae Reproduction/Propagation, Marine Macro-Algae, Diatom AlgaeMarine Algae ID 1, Marine Algae ID 2, Marine Algae Control FAQs II, Marine Algaecide Use, Nutrient Limitation, Marine Algae Eaters, Culturing Macro-Algae; Controlling: BGA/Cyano, Red/Encrusting Algae, Green Algae, Brown/Diatom Algae

Related Articles: Marine Macro-AlgaeAvoiding Algae Problems in Marine System, Algae Control, Marine Maintenance, Nutrient Control and Export, Marine Scavengers, Snails, Hermit Crabs, Mithrax/Emerald Green Crabs, Sea Urchins, Blennies, Algae Filters, Ctenochaetus/Bristle Mouth Tangs, Zebrasoma/Sailfin Tangs, Skimmers, Skimmer Selection, Marine Algae, Coralline Algae, Green Algae, Brown Algae, Blue-Green "Algae"/(Cyanobacteria)Diatoms, Brown Algae

/Marine Selection Series:

The Brown Algae

By Bob Fenner

Turbinaria sp. Red Sea

New Print and eBook on Amazon

Marine Aquarium Algae Control

by Robert (Bob) Fenner

Remember the song: "What's it all about, algae?" By the time this article's over you may feel like shouting out "Kelp, Kelp, call the carps. This piece considers marine algae as a whole, and brown algae in particular; for naturalists and aquarists. What they are, how they make their life, how to select and culture them.

History of Use:

Prior to World War I the study of marine plants was little more than an academic curiosity. With the German cutoff in World War I of potash (as a source of the element potassium) used to make fertilizer and gun powder, and Japanese agar (from red algae) in World War II research, processing and industrialization of seaweeds was expanded greatly.

Lay people, that is vulgar non-aquarists, experience with marine macrophytes is in accord with the implications of the word sea "weed"... noxious, useless, even bothersome; a bunch of stinky litter on the beach attracting flies, clogging their boat prop or fishing line. But these algae and plants fulfill nobler roles in the great circles of life, including useful human purposes; food, fodder, fertilizer, medicinal and pharmaceutical applications. Oh, and also as ornament and more for the marine aquarist!

Marine macro (versus micro) algae serve several important functions.

1) They stabilize the captive environment by introducing beneficial microbes, absorbing nutrients, and producing metabolites that mediate systems biologically.

2) Are good as bio-indicators, showing signs of degrading water quality, before your other livestock.

3) As controllers of undesirable algae growth, macro-algae utilize fertilizer and light that would otherwise be available to noisome forms.

4) Food; most all fishes and invertebrates augment their diets with algal material given the opportunity.

5) As habitat/ornament to break up the environment physically, providing hiding space and beauty.


In terms of biological taxonomy, the algae are grouped as photosynthetic organisms that are not quite plants. Some (the blue green algae, Phylum Chlorophyta) are more like bacteria than even other algae, in that they lack discrete nuclei and protoplasts.

In the grand scheme of things science-wise all algae are part of the Sub-Kingdom Thallophyta, meaning "all about the same plant body"; an allusion to their lack of organized tissues. Algae lack leaves, roots and the elaborate vascular structure (remember "xylem up and phloem down" from high school?) of "higher" plants. But don't weep for their apparent backwardness. As the noted astrophysicist Carl Sagan has quipped; "those cells are smart". Though individual cells are to some degree specialized as holdfasts (attachment organs), laminas, etc. each is capable of photosynthesis, respiration, excretion...

Another sure distinguishing characteristic between thallophytes and "true" plants is their form of reproduction. "Higher", "vascular" plants, Subphylum Embryophyta reproduce via sexual flowering. There are a few species of true, flowering marine plants, but their diversity, abundance and depth-range is limited.

Algae instead reproduce by way of a few variations on the theme of alternating between generations of sexual and asexual spore reproduction; they do not produce flowers. In most cases algae have complex life histories including an alternation of a tiny asexual gamete-producing generation with a sexual spore-producing generation. Please see the accompanying illustration.

Algae are divided into several phyla (or the botanical equivalent, Divisions) on the basis of several characteristics; some phylogenetic, others artificial. The three groups that include the macro-species of interest to us as aquarists, the can be distinguished on the basis of simple color! Green algae are in the Phylum Chlorophyta ("klor-oh-fight-ah"), red algae are the Phylum Rhodophyta ("road-oh-fight-ah"), and our group of brown algae, the Phylum Phaeophyta ("figh-oh-fight-ah"), which unless bleached out and dying are all some varying brownish hue.

The large size and conspicuous abundance of brown algae in Northern Atlantic and East Pacific shores have led them to be termed seaweeds. Though less numerous in species than red algae, browns dominate in bulk in nearly all temperate and high latitude coastal waters. There are several species of smaller brown algae adaptable to warm water systems. It's a shame these aren't offered as often as the various greens (e.g. Caulerpa, Penicillus, Codium) and reds.

Dictyota species, cold to cool to tropical species (plural). Some examples of colonies: right, a reddish patch in N. Sulawesi, below in Cebu (Philippines), and two more bluish ones in Cozumel (Mexico) by Di.F.

Bigger PIX:
The images in this table are linked to large (desktop size) copies. Click on "framed" images to go to the larger size.
Lobophora variegata, Encrusting Fan-Leaf Algae. Fan-shaped blades that encrust rock. Occur in brown, red, green colors as shown in this image made in the Bahamas. And a Lobophora sp. in Redang, Malaysia, and last, St. Thomas, U.S.V.I. The genus is found in both the Indo-Pacific and Caribbean. 
Bigger PIX:
The images in this table are linked to large (desktop size) copies. Click on "framed" images to go to the larger size.
Padina boergesenii, (Kützing) Sonder, 1871. Leafy Rolled-Blade Algae, tropical West Atlantic. 4-6 inches. Here in Cozumel 4/09.
Verticals (Full/Cover Page Sizes Available)
Bigger PIX:
The images in this table are linked to large (desktop size) copies. Click on "framed" images to go to the larger size.

Padina sp., Scroll Algae, a calcium carbonate encrusting Brown Algae in the wild or marine aquariums. This is Padina jamaicensis in Belize.

Macrocystis pyrifera, (Giant) Brown Kelp. Perhaps the largest, fastest growing organism on the planet. Up to two hundred or so feet long, up to two feet more a day.  Here off the Coast of California in San Diego. Sometimes shown in Public Aquariums as a replica, occasionally as the real thing.

Bigger PIX:
The images in this table are linked to large (desktop size) copies. Click on "framed" images to go to the larger size.
Sargassum sp. Cebu, Philippines. Some species in this genus are attached as here, and others free-floating.


Sargassum aquifolium
(Turner) C. Agardh 1820 S. Leyte.

Sargassum fluitans. Sargassum seaweed, Gulf Weed. This is one of the principal algae that makes up the Sargasso Sea in the Atlantic. Has long, serrated fronds with distinctive white mid-rib, smooth spherical gas bladders. Here in Cozumel 08.

Sargassum hystrix, White-Vein Sargassum. Distinctive white central areas on green to brown thalli. Common in the tropical West Atlantic. 4-16 inches in height. Bahamas pic. 

Bigger PIX:
The images in this table are linked to large (desktop size) copies. Click on "framed" images to go to the larger size.

Stypopodium zonale, Leafy Flat-Blade Alga. Flat blades that are irregularly split and branched. Attached to hard substrates. Cancun, Mexico. 

Turbinaria ornata. Kona, Hawai'i pix. 

Verticals (Full/Cover Page Sizes Available)

Bigger PIX:
The images in this table are linked to large (desktop size) copies. Click on "framed" images to go to the larger size.


As stated above algae have not true roots, leaves or flowers. The whole algal body is termed a thallus. The portion that attaches the thallus to the substrate is the holdfast; the erect stem-like stalk is called the stipe (like stripe without the "r"). Almost all brown algae are attached; a notable exception being the classic genus Sargassum which makes up the bulk of the floating masses of the Sargasso Sea.

Brown algae are macroscopic for the most part with no unicellular or colonial forms. Though phaeophytes contain the requisite photosynthetic pigments, chlorophyll a & c, they are characteristically colored brown due to the accessory carotenoid pigment fucoxanthin.


Let me try out another way of making known to you the concept of "alternation of generations"; it's kind of a hard concept to grasp. Imagine a given species of algae. Instead of only two types of individuals, one male and one female, as with you and I, the algae you encounter can be one of three possibilities, male, female or a sporophyte. This is a little tricky... the male and female individuals are structurally very different from the sporophyte. Generally they are very small, possibly microscopic; and they are haploid organisms, that is, their cells are composed of one-half the full complement (diploid) of chromosomes. The sporophyte arises from the flagellated spores of the gametophyte getting together under fortuitous circumstances and develops into the larger, sometimes huge specimens that most of us recognize as seaweeds.

One more time. Algae are spore reproducers lacking the familiar reproductive structures of flowering plants. In green and brown algae these spores are usually motile, flagellated unicells produced in sporangia (compare with ferns). Spores produced by the sporophyte generation of algae give rise to the gametophyte generation which reproduce via motile flagellated gametes.

Generalized life history of a brown algae. 

How to Get Them:


Brown algae are abundant along both coasts of the U.S. in cooler waters. They are present in smaller sizes and numbers, though not as conspicuous in warmer areas.

Going hunting for your own algae generally requires permits, otherwise known as licenses, okay another tax. Check with your local, state "fish and game agency" regarding.

A word about the drift, as in "do you get my". Storms bring in a great deal of algae et al. material to the beach; mostly dead and dying. Avoid it.

Low tides and "minus" tides are productive times for collecting specimens. The same guidelines apply for algae as for invertebrates and fishes. Be discerning about what and how much you take! Pick only a few, small healthy individuals and pack them loosely and carefully for the trip back. I suggest double-bagging with enough water to cover them, and placing the bags in "fish" boxes or sturdy buckets.

For most varieties of attached algae, chipping a small piece of the substrate which it is attached to is advised. Check with your local laws and Wear safety glasses and gloves when smacking rocks with hand tools. A few notes concerning processes to go through before introducing "wild" algae. These organisms must be handled the same way as fishes and invertebrates; i.e. with a quarantine, or at least dip procedure to remove pollution and undesirable critters. Beyond that I suggest you acclimate them through a water interchange procedure.

Oh, and a word regarding using collected algae as food. This is a great idea as a blended food additive or supplement, but do rinse and freeze the material first for the same reasons as above.


Is the best, and for those who live away from the sea, the only way to acquire macro-algae. As compared with collecting your own, what do you get? A guaranteed, live specimen with a cultured pedigree no less; no chemical or biological contamination. In total a supremely pre-adapted aquarium captive.

Sources for buying include your local shops and mail order. The specialty marine outlets can order wild and cultured algae year round. Give them the following if they need a supplier: Aqualife Research Corp., 700 S.W. 34th St. Ft. Lauderdale, FL mailing address. Or their facility @ 33315 Walker's Cay, Abaco, Bahamas, 305-359-1409. Godfrey Waugh and staff also produce large quantities of tank bred and reared Clownfishes and neon gobies.


Is it healthy, dying or what? If the algae is turning white, falling apart, or yielding an odd smell to your water, it's time to give it the old heave ho.


Maintaining a tank with macro-algae is like other types of marine systems. Some arrangements are easier/harder to keep going than others. Obtaining good, healthy individuals and providing a suitable habitat is key to any system's success.

Research the algae you want to keep. Most require cold to temperate water, rigorous circulation. Adequate lighting and nutrient availability are simpler matters.

Considering their original source, the habitat requirements of brown algae are easy to understand. They're for the most part relatively stable physically and chemically, due to the size of the system, the ocean shore, and the circulation afforded there. A stable high density (1.023-1.025), maintaining a pH in the low to mid eights is critical. A pinch of sodium carbonate or bicarbonate (Arm & Hammer) and frequent partial water change (20% per month) should do.

As regards lighting; different species have more/less need for quantity, quality of light. Most green and red species require far more than brown algae. Mixed, broad spectral fluorescent sources are recommended for 16-18 hours per day. Regularity is important, so I would incorporate an automated timer system. Too much light is practically impossible. Some stated rules of thumb are @ 3 watts per gallon; if you have a meter @ 16,000 lux at the algae depth.

Temperature ranging too high, too long is often the cause of loss of these algae. It is strongly recommended that you acquire a chiller with most species especially if your place gets hot during summer. Tropical green and some red species are easier for warmer, non-chilled systems.

Metal and dye medications will kill all algae, desirable or otherwise. Treat fish elsewhere; most preferably via quarantine and/or dip procedures.

Water chemistry notes. Ammonia, nitrite, nitrate; obviously the tank must be cycling before algae can be introduced. Utilizing tests for nitrogen pollution is a useful window to the overall condition of your systems water. You want to keep all nutrient levels non-selectively low. What I'm trying to convey is that you should not rely on chemical filtrants, carbon, resins, clays, and their combinations. Keep stocking densities low and/or balanced with other inputs/outputs.

Phosphate must be low; otherwise micro-algae (diatom scums, unicellular and colonial greens) will overrun the system and cover your macro-algae.

Thiel and others endorse the use of chelated iron (to 0.1ppm and more) through a liquid fertilizer. Many authors go so far as to suggest regularly adding prepared nutrients to the system. High-tech fanatics even monitor and adjust carbonate hardness (to at least 15 German degrees (DH), convertible to ppm by multiplying times 18) and utilize carbon dioxide infusion. For fancy scientific folk this can be translated into a redox level of greater than 300 mv.

All these embellishments are unnecessary to the simple success of keeping and growing these algae.

A Conclusion:

Marine botany as a part of the aquaristic interest is at an extreme infancy. This field will hopefully come into being faster in the West than its freshwater equivalent. Marine algae produce more than ninety percent of the oxygen on this planet and make up the bulk of coastal biomass. They are readily available and capable of our culture; they perform several important functions and are beautiful.

Bibliography/Further Reading:

New Print and eBook on Amazon

Marine Aquarium Algae Control

by Robert (Bob) Fenner

Brawer, Marc. 1971. So you want to keep marine plants. Marine Aquarist, 2(2):71.

Caribaldi, Lou. 1973. Seaweeds are not weeds. Marine Aquarist, 4(4):73.

Dawson, E. Yale. 1966. Marine Botany, An Introduction. Holt, Rinehart, Winston.

Dawson, E. Yale. 1975. Seashore Plants of Southern California. University of California Press, London.

Dawson, E. Yale. 1975. How To Know The Seaweeds. Wm. C. Brown Co., Iowa.

Fenner, Bob. 1989. Waterscape Maintenance: Some Notes on Algae & their control in Biological Ponds. Freshwater and Marine Aquarium, 6/89.

Fenner, Robert. 1990. Ornamental Algae; How to Raise & Market It. Pet Dealer, 10/90.

Lobophora reference: http://www.globaldialog.com/~jrice/algae_page/lobophora.htm

Niesen, Thomas N.. 1982. The Marine Biology Coloring Book. Barnes & Noble.

Thiel, Albert J.. 1988. Keeping & growing marine macro-algae. Freshwater and Marine Aquarium, 8/88.

Become a Sponsor Features:
Daily FAQs FW Daily FAQs SW Pix of the Day FW Pix of the Day New On WWM
Helpful Links Hobbyist Forum Calendars Admin Index Cover Images
Featured Sponsors: