New Some Info RE: Hydrilla

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I had posted this in the plant section yesterday but got no traction.

I'm thinking maybe this area is visited more often and somebody can chime in.


Recently built a 25x25 pond in my yard. Started as a 3x5 but I got carried away on the tractor. Living in N. central Florida stocking with plants is easy. I find them everywhere. Many of them are considered invasive so no issues taking them from public waters.

I have some nice floating "mats' of water hyacinth and a coupe of what I believe are rush in pots.

Just came home from the Ocala National Forest with a plastic bag full of hydrilla.

Everything I read says it is extremely invasive and very difficult to eradicate. A couple of threads I have read speak of it taking over larger ponds (2 acres and larger).

My question is as follows is it OK to let this loose in my app. 7,000 gallon pond? I would think if it gets too invasive I could easily rake some of it out as my pond is not immense. I see the difficulty in a 2 acre or larger pond but in a 2x25 can I control it?

I would think it would be a good oxygenator.

Lastly, I currently have about 100 goldfish amongst the hyacinth and rush. Nice oxygenator stone as well

https://www.amazon.com/gp/product/B007BK76YK/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1

Pond is crystal clear and I think iI have a nice cycle going. I am considering 2-3 koi and wonder if they prefer hydrilla over my water hyacinth? I have read on this forum that if one feeds the koi they may not bother plants. Yea or nay on the koi??

Any help is appreciated.

BTW: I suppose I could also try "fancy" goldfish like shubunkin.
 

Meyer Jordan

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Are you sure that it is Hydrilla and not Egeria or Elodea two similar but different species? Not that it really matters as all three are highly invasive in eutrophic (nutrient laden) waters. a;though Elodea (Anacharis) is the least invasive of the three.
The problem with aquatic plants that have this spreading ability is the fact that they will eventually block sunlight from penetrating the water column and as a result hinder, if not completely stop. any photosynthesis that is algae based. This could affect the Dissolved Oxygen levels in the water column negatively regardless of the Oxygen supplied by these particular plants.
They can be beneficial in that they provide mini-habitats for micro- and meio-organisms within the plants foliage thus providing a food source for larger pond organisms including fish. Many times supplemental feeding of the fish can be completely eliminated as all nutrient needs are met within the pond itself.
I would verify which specie of plant I had. If it is Elodea then I would keep it. If not, I would toss it and secure some Elodea (Anacharis). You do not want to spend all of your spare time thinning plants with a pond rake. It can be a tedious chore.
As for whether or not the Koi will eat it depends on what they can find on the bottom of the pond as they are bottom-feeders and prefer high protein like insect larvae, snails and nematodes as diet mainstays.
 

addy1

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Welcome to the forum!

I would be careful with it:

  • Hydrilla can grow in almost any freshwater: springs, lakes, marshes, ditches, rivers, tidal zones.
  • Can grow in only a few inches of water, or in water more than 20 feet deep.
  • Can grow in oligotrophic (low nutrient) to eutrophic (high nutrient) conditions.
  • Can grow in 7% salinity of seawater (Haller 1974).
  • Temperature tolerance: hydrilla is somewhat winter-hardy; its optimum growth temperature, 20-27o C (68-81o F); its maximum temperature, 30o C (86o F) (Kasselmann 1995).
  • U.S. southern populations overwinter as perennials; northern populations overwinter and regrow from tubers.
  • Can grow in only 1% of full sunlight.
  • Low light compensation and saturation points and low CO2 compensation point make it a competitive plant because it can start growing in low light before other plants do (Van et al. 1976; Bowes 1977).

  • Forming dense stands of very long stems (25 ft.) in the water.
  • Reproduces mainly by regrowth of stem fragments; also reproduces by growth of axillary buds(turions) and subterranean tubers; tubers can remain viable for more than 4 years (Van & Steward 1990).
  • A single tuber can grow to produce more than 6,000 new tubers per m2 (Sutton et al. 1992).
 
Joined
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Addy and Meyer, Thank you.

I am a bit lost at this point. I sent a photo of the plant to a friend in N.Y. who professes to know "everything" about ponds. He said it is not hydrilla but does not know what it is. I have attached a couple pics, sorry for poor quality.

FWIW: i see no tubers and this as just floating at the edge of the lake not anchored but maybe it was pulled up by a boater?

Meyer: I know it can be tedious to rake out but in a 25x25 is it too much to pull a bit out once a month? Maybe I should toss it?

Thanks to both of you again.
Lastly:
20171211_081328_resized.jpg
20171211_081306_resized.jpg

Thoughts on Shubunkin vs Koi??
Appreciate the help
 
Joined
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Thanks, meyer.

I looked at some I.D. pics from UF (University of Florida) and it did not appear to be one of the invasive species.

It just may be pond weed. i have forwarded pics to a couple of aquatic guys at U of F.
Thanks again.
 

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