Biological Diversity In A Koi Pond

[MikeM]

Every Spring for the past 4 years, I have had an organism grow on maating in one of my filters. It has the appearance of a sponge, and I've begun to call it a "freshwater sponge". However, I really have no idea what it is. It prefers the blue mat, but once established will spread to adjoining hard surfaces. Over the years, salt, supaverm and ProForm C have been used in the pond with no noticeable effect on it. When the hot Florida summer weather arrives, it generally disintegrates. There are small reddish "balls", not even the size of a pinhead, that form within the structure. These are released when it disintegrates. The filter has a large flow of water through it and is covered to prevent any light from entering. The water is fairly well pre-filtered. It is rare to have any sludge build up on these mats. What you see is as dirty as it gets. Anybody have an idea of what this is??

[Bob Hart]

No idea Mike.

What happens if you aerate this matting cartridge, does it break up and go away? Presume the cartridge isn't usually aerated?

[B.Scott]

Mike,
Is your filter completely in the dark?
I get the same stuff but it grows under the inside of my bottom drain lid. I appears not to need any light. I call it a sponge as well. I have no idea what it really is.
B.Scott

[Bancherd]

I have similar whitish, sponge-like organism growing on the inside of my prefilter chamber, NEXT to an airstone. Mine was very short, and thin, only about 1 mm high; covering about 5 sq. inches.

The area is completely in the dark. I was in the rush and did not have time to put it under a microscope.

Next time, I will take a look at it.

[MikeM]

This is progress! Three of us have it in dark spaces with heavy water flows. We just might find out it is everywhere, but growing places nobody ever goes. ... like all those pipes feeding filters by gravity flow.

Bancherd: Please share your observations with the scope.

Bob: I do not think aeration would bother it so long as not in the direct current of a heavy stream of bubbles. I'd estimate the flow rate in this filter at 1200+ gal. per hour. (The water has been through a leaf net, two skimmer mats, a chamber of brushes, and a couple of cubic feet of submerged bioballs before reaching this small section of mat.) The mat is in an up-flow chamber. When the pump is on the "sponge" is submerged. If I remove a section of the blue mat and swish it through a bucket of water, the furthest extensions of the "sponge" will break apart, but the base portions remain affixed and grow back. I can gently push it down and it will return to its original shape when water flows over it. If I push down hard, it becomes mush and the smashed portion washes away in the current.

B.Scott: Absolutely dark. The cover is black agricultural groundcloth. Some air movement occurs around the edges and water will slowly drain thru it, but light does not get thru.

[Fishbreeder]

Yes!

Those are sponges, freshwater sponges.

They don;t need any light, just flowing water. They can stop up a 48" pipe under the right conditions. In a large recirculating fish culture system I once managed (about 685 million gallons) that flowed about 48,000 gallons per minute through the system, sponges were a big problem. The system was very rich as it had a standing crop of about 7.5 million pounds of fish and was fed about 250,000 pounds of feed a day. The sponges grew very well and caused the system to back up.

They are easy enough to clean up, just brush off and throw away. Or pour some chlorine through the pipes and media, kills the sponges, but everything else also.

They are very effecient filters and will collect all manner of solids as food.

Brett

[MikeM]

Thanks, Brett. I read what you posted, but the idea of this thing blocking a 48" pipe is mind-boggling! But, so is that much water & fish & feed!

At this point I'm not looking to get rid of it, although I would if it started to block water flow. I expect it will grow considerably larger thru mid-July. Then begin disintegrating until nothing is visible by mid-August. I expect it re-grows beginning with cooler water temps in December, but not really noticeable until February/March.

Do you have any references to what it feeds on? Only fine particulates reach that section of the filter. ......But it does get a population of midges (or something similar) that swarm out when the cover is lifted each week ... larvae are swept up into the filter where they mature but cannot fly free until the cover is lifted. All kinds of life in & around a pond.