AGA 2008: Benito Tan: Aquatic Mosses

November 17th, 2008

Benito TanBenito Tan gave a fascinating talk at the 2008 AGA Convention about aquatic mosses. One of the really nice things about Dr. Tan, is that he seemed to be somewhat familiar with both the scientific side of mosses, as well as, their application in the aquarium hobby. This allowed him to tailor the talk to exactly what a room full of 200 hobbyists wanted to hear.

He started his presentation detailing why it’s so difficult to identify mosses, and aquatic mosses in particular. Most aquatic mosses only grow their sexual growth under water. This means that your best guess at identifying them is by placing them under a light microscope so that you can look at cell structure, leaf shape, and branching patterns. Still, many times you still can’t be sure without the non-sexual growth of the moss.

Dr. Tan then described how Java Moss has been called many things in the hobby since it was introduced. Again, many of these problems stem from the inability of hobbyists to correctly identify mosses, especially when they can look different under different growing conditions. He also talked about a number of mosses currently being sold in Singapore.

Mosses Sold in Singapore

He’s just recently started using DNA to try to identify various mosses, but described how even DNA presents its challenges. He said that DNA can almost always help you figure out an unknown moss’ genus, but you may still have to rely on more traditional methods to then determine the species. The reason for this, is that there are not enough known indicators for moss DNA to key on to find exact matches.

Other Mosses Sold in Singapore

Dr. Tan also talked about a liverwort, Subwassertang, that’s been making its way throughout the hobby. What was most surprising is that despite its resemblance to Pellia, it is actually not a liverwort at all. In fact, Subwassertang is really a fern gametophyte that’s missing the female sex organs so it never matures to become an actual fern.

Life Cycle of a Fern

He’s done some research on the gametophyte, and believes that it is a fern from the Lomariopsis genus. What’s most peculiar, however, is that this type of fern is actually a branch climber, that lives entirely in trees. He doesn’t know why that type of fern would have an aquatic gametophyte for reproduction. Below is a picture of what the terrestial fern would likely look like.

Lomariopsis Fern Frond

Dr. Tan ended his presentation with a rather enticing slide with two aquatic mosses that he believes would make great additions to the hobby. Privately, when I asked him if he thinks they will actually make it into the hobby, he said that it’s only a matter of time.

Possible Canidate Mosses for the Hobby

Another one of my most anticipated talks, Dr. Benito Tan gave an excellent and informational presentation. In addition, he also had a sharp sense of humor, which aided him during his talk. And for everyone that see’s terrestial mosses on the forest floor, and tries to put them in the aquarium, Dr. Tan urges you to stop drowning mosses, for he’s in favor of a “Cruelity to Mosses” society to champion their right to live undisturbed. A great speaker, and a great talk.

8 Responses to “AGA 2008: Benito Tan: Aquatic Mosses”

  1. Al Says:

    You seem to have a green thumb for aquatic plants. Do you know any methods of making java moss grow faster than usual, I’ve heard of various methods such as indirect light, cool water, and co2 injection. I have also heard of growing it emersed and spraying it with water ever so often. Which method according to you would work best?


  2. guitarfish Says:

    Al, I can’t say that I haven’t tried all of these things (indirect light, cool water, or emersed), and I haven’t directly compared multiple methods with Java Moss, so I can’t give any conclusive advice. I will say that moss grows quite fast in all of my high-tech tanks (high tank, high CO2, fertilization), and slower in the tanks without those things. I hope that helps out a little bit.

  3. Mark F. Says:

    I think the correct spelling for that fern gametophyte is probably Susswassertang, not Subwassertang. The Germans, who presumably were the first to bring this species into the hobby, use a letter for lower case double-s (ss) that looks like a capital B, but with an opening at the bottom; this causes a lot of confusion in translations. The literal translation of “Susswasser” is “sweet water”, meaning fresh water (as opposed to salt or brackish water). I’m not sure what “tang” means; presumably it’s the German name for some type of marine algae which the fern gametophyte superficially resembles.

    It’s been suggested to me that “tang” might mean “fern”, so that the name might actually be “Subwassertang”, which would then translate roughly as “under-water-fern”. When I spent a year living in Germany, however, I frequently went hiking in the woods with German relatives of mine, and they referred to ferns (when asked) as “farnen” … also, the more common German phrase for “under water” is “Unterwasser”, not “Subwasser” … so I’m sticking with “Susswassertang” as the correct spelling!

  4. guitarfish Says:

    I believe you’re right Mark. I spent a few years studying German myself, but was going by the name most seen in the hobby. I had always thought the translation was “Fresh water seaweed,” but I certainly would not bet my life on that.

  5. KeroKero/Corey Says:

    Woah, very cool info on Susswassertang (killed mine, dammit!) and totally not what I was expecting. Interesting little glitch in evolution I guess (no one said evolution was always going the right way…). Just makes it more interesting to me that it was even found!

    In response to Al, I’m not sure why you want to grow it faster than usual but the idea is the same with all plants… optimal light, nutrients, and temps. has been a good resource for me. The indirect light bit probably has to do with direct light warming up water above the optimal range for the moss, but java can take pretty warm. I’ve not found growing it emersed to be any faster, and once established the rate of growth had a lot to do with optimal light, nutrients, temps, and staying relatively wet. I’d just recomend growing in in similar conditions as what you’re eventually going to use it for, and just be patient!

  6. Sherry Says:

    I just posted much information (on research I had done on this species) and concluded it was the above but wasn’t sure how it seemed arrested at the gametophyte stage (having grown ferns from spores and understanding the process).

    Anyway, message missing when I hit submit comment (maybe too much)? and took a long time to compile the original research for posting here so won’t now.

    The research was in response to another forum member posting a photo and wondering what “it” was – fern, algae or liverwort? (interesting links, beautiful photos – of all three and more, so if any one interested I will just email entire post)

    Süßwassertang. That means “freshwater seaweed” in German.

    I studied two years of German, but hadn’t remembered much so asked my x. He is Austrian and I asked what the word meant. Mark, your thoughts on spelling and meaning are correct.

    He said actually the above spelling is correct – in translation it would more correctly be suesswassertang. He said Süßwasser meant “fresh water or sweet water” and tang more like sea kelp, seaweed or that sea stuff (he has no interest in any of this, lol and was not 100% sure). He looked up the word tang in his dictionary and tang means seaweed. He said his native tongue is equally confusing to him, lol.

    The research I did makes sense, since ferns are primitive plants as are these (hence the spores) and at some point many of them (liverworts, algaes and ferns) look similar, land or water, fresh or salt, even if not related at this point (the evolution of them would be interesting).

    (esp the usda files which post hundreds of photos – it is amazing the variety).

    Best Sherry

  7. geoff Says:

    elow sir…i just wanna ask about the mosses present in the philippines?? i would like to know about some species with antibacterial properties..thank you

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