Ok the title is a bit over the top but in a round about way it is true. Many swimming molds live in and swim through the thin film of water on wet plant leaves and ruin many important crops during extra wet growing seasons. These molds often have a very negative effect on agriculture and are directly responsible for the deadly Irish Potato Famine.



Some make their homes in moist frog skin and cause a deadly disease that has been decimating frog populations around the world for several decades now. While others cause a common fuzzy white growth of mold on tropical fish.

These molds in at least some stages of their complex life cycles propel themselves through water with the aid of tiny whip like structures called flagella. Flagella are those long whip like structures that are found on some cells such as sperm cells and are one celled plant like Eugenia protozoans which push themselves through water.

In his book The Fifth Kingdom Dean Kendrick noted mycologist (mold biologist) discusses three phyla (large groupings) of swimming molds.

1) PHYLUM CHYTRIDIOMYCOTA

The first group is known as chytridiomycota these are true fungi and they have a single flagellum at the rear of the cell, this flagellum propels the mold cell through the water just like the flagellum at the rear of a sperm cell propels sperm cells. Around 1998, Joyce Longcore determined that a type of chytridiomycete mold was causing the death of many frogs around the world by infecting their skin. You may not have heard of it but widespread frog deaths have been a serious concern for decades now.

2) PHYLUM HYPHOCHYTRIOMYCOTA

The 2nd group that Dean goes on to discuss is the kingdom Chromista phylum hyphochytriomycota. They have a single hairy flagellum at the front. Though similar to the above molds, these are not true molds.

3) PHYLUM OOMYCOTA

The Third group is the kingdom Chromista phylum oomycota, they seem to be split and cannot make a clear decision on if it is better to have one smooth flagellum at the rear or to have a hairy one at the front, so the oomycetes have opted for two flagella at the side, one of the two is a hairy flagellum that points to the front and the other is a smooth one that points to the rear.

Oomycetes make up the water molds that cause many common fungal infections in fish including tropical aquarium fish, as well as downy mildew that cause serious crop damage around the world every year. Most importantly oomycetes caused the Irish Potato Famine. This famine caused the death of one million Irish people and caused millions to emigrate from Ireland including the ancestors of Al McNamara of Abode Inspections, one of America's first ASHI home inspectors. He was my mentor and introduced me to the home inspection field in 1993.

Some of the above organisms have a flagellum during its reproductive state only while a few exist as a single celled flagellated mold its entire life. Most of the above live in water, moist soil, or in the thin film of water on wet plant leaves. A few even live on the surface of single grains of flower pollen. Obviously, none of the above water molds are common in moldy homes. However, it is interesting to understand that these microscopic molds swim and cause serious negative impacts on humans, plants, and animals around the world.