Valonia, Ventricaria, Dictyospheria
Bubble Algae

The four main forms of green so-called Bubble Algae (Chlorophyta) that we nowadays quite commonly encounter in reef aquariums are:

The reason they end up in the aquarium is because they come in with rock you place in the tank. Often when the rock arrives, there may only be spores and these may be hidden inside the porous parts of the rock itself. Small algae may be present on the rock, but they may be so small that you actually do not see them. Many other reasons exist

I have known one particular instance where a hobbyist suddenly started seeing Valonia in her tank, and had no clue what so ever where it came from. She had not added rock and the tank was over 2 years old. No such algae had ever appeared. She was stumped needless to say.

Upon probing her for a long time into what she had done to her aquarium in the last several weeks we could not find any real cause either. Further questioning revealed that to seed her live rock better with bacteria she had taken some water from a friends tank who used partial natural sea water and added that to her tank, to determine if there was any benefit to doing so (using natural sea water that is). The interesting part was that this had taken place about 4 months before the algae actually showed up.

Since nothing else could explain the appearance of the Valonia algae, a phone call was made to the friend and, sure enough that aquarium had a small amount of Valonia in it. The transfer of algae occurred as part of the water addition, and probably in the form of spores, or real small emerging algae, smaller than the visible eye can detect (50 microns).

At times too, any of these algae can be present in a dormant state, awaiting for the water quality and lighting to get propitious to their growth. When this happens, they will suddenly start growing and become visible to the hobbyist. For instance, when the spectrum of the lighting diminishes and picks up more yellow and red wavelength light, the algae may suddenly start to grow because these two lightwave colors promote the growth of algae. This is well know to freshwater hobbyists who try to grow plants. Indeed they use that kind of lighting to promote plant growth (the spectrum at that point is usually around 3300 to 3500 Kelvin degrees).

All four are quite different from each other and do not pose similar problems for the hobbyist; in fact the first one and the last rarely cause problems at all! It is Ventricaria ventricosa that grows so rapidly and can overtake and aquarium in no time. They proliferate very rapidly indeed. Most hobbyists do not seem to have a problem with them but those who do definitely need to know how to remove this pesky algae from their aquariums.

Valonia species normally grows at a much slower rate and is not known to cause great outbreaks and rapid spreading, although some hobbyists report they do have them in their tanks in large numbers, some suggesting too many. Of course, one has to be sure that the identification has been made properly to begin with. Valonia species is often confused with Ventricaria species by the way.

The graphic drawings clearly demonstrate the difference between the 3 types. The graphics are of A. Thiel and D. Lark.

Note that the graphics are not to size. The respective colors are:

Valonia Species Algae

Valonia is a nearly perfectly round bubble, dark green in color, and not very shiny. The green is close to what we know as bottle green. It has a soft outer skin which feels sort of like it it has real tiny filaments on it. Although it looks very smooth it does not really feel all that smooth to the touch. I personally like Valonia in the tank. It is a real nice alga to have. Big bubbles look particularly appealing.

Unless Valonia algae starts to grow all over the place in the aquarium, there really is no need to be concerned about its growth and proliferation. Most of the time you will have algae bubbles in several parts of the aquarium and the bubbles will, more than likely, be of certain of different sizes. That, in fact, is the nicest way to have them in your tank: several, spread over the tank and of different stages of growth.

Although you (we) do not "consciously" introduce Valonia Algae in the tank, at least not most of the time, the alga may suddenly appear in your aquarium. The reason often is that it may have come in as very small algal bubbles, or spores, on the live rock. Often these algae will be so small that you do not see them, even on close inspection of the rock.

Place enough lighting (lighting intensity) over that aquarium and, suddenly, algae will start to grow. This could very well include Valonia. If this happens consider yourself lucky as, in my opinion, Valonia is a very desirable alga to have in your reef.

Valonia species algae have a real soft outer skin that pierces easily. If you do attempt to remove them you should not pierce them as you will add thousands and thousands of spores to the water when you do so. Valonia can only be removed by sucking it out with a powerful suction.

While I do not recommend that you remove them, if you really have too many, you can. They need to be removed by literally sucking them out with the intake of a power head, leading to an exterior vat where the alga and its inside fluids is collected. Do not let the fluids get into your tank or you will enduce many more to grow, defeating the purpose of the exercise.

Dictyospheria Algae

Dictyospheria Algae are really more an agglomeration of algae than one algae. Small round bubbles grown in tight vicinity to each other and in an irregular pattern. They will follow the shape of the rock. The Jo-Bert that we set up electronically (and you can DL all the files on what we did from this WEB site), now has this alga in it. It suddenly appeared on a piece of rock and has spread to about 2.5 inches in diameter.

Dictyospheria is, again, a slow growing algae. It may turn up in your aquarium if it come in on live rock you own. It is not nearly as common as the other two mentioned here though. Even when it turns up, it grows so slowly that it is no reason for concern.

Dictyospheria algae are soft and burst easily. Again, as with Valonia, breaking up the bubbles will put thousands more spores in the tank and can lead to much more of these algae in your aquarium..

Since Dictyospheria does not spread rapidly there is no need to be concerned about its presence in the reef tank. It will not cause any overgrowth. It is a nice algae to have in your tank.

Ventricaria ventricosa Algae

Ventricaria ventricosa is the tear-shaped alga (sometimes, but not often, round) that is so rapid growing that it can overtake a aquarium in no time and make it very unsightly looking.

Ventricaria ventricosa is an algae that feels hard to the touch. Its color is light to medium green, not dark or bottle green as the algae Valonia's color. It is often confused with the later but is a totally different alga.

When Ventricaria start to spread in the tank, hundreds can appear in just about any area of the aquarium and the proliferation can be very fast indeed.

It is best to start removing them as soon as you see them. Don't let the situation get totally out of hand! If you do, there will be so many of them that you may not be inclined to even start the removal process. This is, indeed, the algae that spreads really quickly and that needs to be removed from the aquarium.

To remove Ventricaria ventricosa safely, proceed as follows:

Remove as many as necessary, and throw them away. Alternatively give them to a store. Keep them in water and they will do OK as long as they are placed back in a tank with high calcium levels.

Ventricaria ventricosa is not an algae that does damage per se, but when hundreds and hundreds of specimens are present they can overgrow areas where corals are placed.

Although no damage to corals has been reported from the presence of Ventricaria ventricosa, the corals will close somewhat if Ventricaria ventricosa is touching it.


Bryopsis is in many respects similar in the ways we need to deal with than Valonia. The only difference is the appearance and the color. Ridding the tank of this algae is usually not necessary as it does not normally overgrow the tank. If it does you will need to siphon it out as described for Valonia.

Do not pierce this alga in the tank as it will then release spores by the tens of thousands and more and more algae will grow as the spores settle on rock and give rise to new growths.

If you notice them on rock that you receive you may wish to remove this alga just as you may wish to remove any other bubble algae described. This is certainly one way to prevent any of them from starting to spread sooner than you want. Not all tanks will see them appear, but if they do, intervention should be dictated by the numbers. If you only have a few, do not worry about them.

Should you have any questions about this article feel free to leave me a message directly from this document: Email Me

I will be glad to answer any questions you may have.