Brown Algae: Good, Bad, or Ugly?

[thlosey]

Hi,

A couple days ago I noticed several small brown shoots growing out of one of the Fiji live rocks in my 10g Nano. This morning I took a closer look and saw that they are starting to grow small blades that look very similar to the Fucus species of seaweed that are common to the Maine coast. Could this be a tropical species of brown algae? I have never heard of anyone keeping brown algae in a reef, so I am very curious if this is the case. I don't have a digital camera, but I will try and take some photos and scan them. Thanks for your help.

Ted

[horge]

Hi Ted,

Get those pics

I'd be surprised if a reeftank DIDN'T have any brown algae (Phaeophyta) in it: apparent absence often merely means that the herbivores are keeping them trimmed down to near-zip. If you take any piece of live rock in a balanced, apparently-problem-alga-free tank, and cage the piece, it's almost guaranteed you'll see shoots of greens, reds and browns very shortly (don't even THINK of mentioning cyanobacteria, brrr).

Is husbanding of brown algae ideal for a reef tank? No. Some browns leak a lot of phenol-ish goop into the water, and this seems to suppress coral growth. It seems to affect ramose/branching coral more than massives: if you slow down a Favites "pineapple" coral, it still remains structurally sound, but if you slow down a more fragile Stylophora, it cannot keep up with fragmentation damage and predation ---but I digress yet again, hehe.

I guess what I was leading up to is that nearly ALL algae are competitors for leibensraum with coral, --the little Nazis-- and will employ numerous strategies to edge out all rivals. So, you want to generally suppress all algae

Still, I'd love to see dem pics!

HTH
horge

[thlosey]

Thanks for the info. I am now sure that the shoots are brown algae. I don't have anything in my tank except three Turbo snails, so I am not too worried about the algae yet. I would like to know how best to control them. I don't think I can keep a tang in my 10 gal tank, so should I just try to keep the algae cut back?

Ted

[horge]

Hi Ted,

3 snails (I prefer Trochus to the more fragile Turbo) in a 10g just might not be sufficient, depending on the rock surface area. Still, you should be able to tell if they have a tooth for the brown algae or not. (If not, then all the Turbos in the world won't help)

If you can't get a pic and post it here, do a search for MOP Magruder and Hunt Seaweed Identification (that webpage has moved around a lot). It'll take you to a very user-friendly, entry-level ID guide with pics.

Keep in mind not all brown-colored algae are Brown Algae, so rummage around a bit.

ID will help determine how aggressive you need to be against the alga, and how.

HTH