Brushing algae off rocks - harmful to fish??

[Telkwa]

Good morning to everyone!

I'm probably close to the template for your typical small pond owner. I don't enjoy the pond as much as I thought I would, and there's always some problem to deal with. The pond is roughly 2500 gallons.

So here's the latest problem. Our "shoreline" is built up with rocks, from fist sized to maybe a foot or two across.

I was scrubbing algae off those rocks. My wife asked me to stop because she's concerned the loose algae will clog the fish's gills. When I scrub I usually run a second pump to a temporary fabric filter so that some of the loosened algae is transported out of the pond.

Is this a concern? I can see maybe if I scrubbed so much algae that I created an impenetrable goop but it's not like that.

 

[Mmathis]

First of all, which kind of algae are you talking about? Is it string algae [it's all stringy with fibers] or the [I call it] blanket algae -- the squishy, slippery stuff that grows on the liner? The fish nibble on this last kind.

Not sure about the algae clogging gills, but I don't see that as an issue, especially with good filtration.

Here's one technique that I've heard some of our members have used with success. They spray hydrogen peroxide on the rocks. Your filters and your extra filtering should clear up any dead stuff.

I'm sorry to hear that you're not enjoying your pond

 

[Telkwa]

I think most of the prob is string. I can drag a net through and pull up 3 foot long sheets. I've been cruising threads and it looks like hydrogen peroxide and/or something like PhosOut might be a fairly easy thing to try.

My wife doesn't have the stomach to weed out the young fish so overpopulation is part of the picture. Garter snakes have killed a few fish this summer and I'm hoping they continue. Don't tell her that...

 

[Mmathis]

@Telkwa A good way to get rid of string algae is with a toilet bowl brush [not previously used on toilets, of course]. You get some algae in the brush, then twirl it and pull the algae out.

Do you have any plants in your pond? I can tell a BIG difference in the amt. of string algae based on the number of plants that are actively growing. The plants compete with the algae for nutrients.

Also, too much sun exposure will increase algae growth. Does you pond have any shade and/or do you have plants like water lilies that cover and shade the water?

 

[Big Lou]

Used absolutely per instructions liquid algaecide. will destroy your algae without harming your plants or fish. Tetra sells algaecide. I cannot over emphasize that algaecide be use exactly as directed by the manufacturer. When properly used the result is outstanding. Questions welcomed.

 

[Tula]

I have never heard of algae clogging a fish's gills.

 

[Telkwa]

OK, thanks, guys -

I didn't see it as much of a concern. They aren't trout.

I did kill a fish one time in a previous pond by choking its gills off. We were moving everybody out. Couldn't catch the last few fish so we sucked the pond down to less than a half foot deep. By then it was getting pretty thick, especially with the fish wriggling around and stirring things. We moved the fish successfully, but you could see one of them had inhaled a bunch of algae and whatever else was on the bottom. There was stuff hanging out of his gills. He died a few days later. But that was a much more extreme event than scrubbing off some rocks in a full pond.

My wife is also very reluctant to dose the pond with chemicals but I think it's time to do what I want to do.

Turtle Mom, I've got a very stiff brush on a 5 foot handle - some sort of floor scrubber or something - that works pretty good for manual removal. Same basic procedure as you describe - sort of a spaghetti twirl kind of motion - and I can drag big globs out. Easier on my back than a toilet brush.

 

[Big Lou]

FYI
TetraPond Algae Control Water Treatment

Controls Green Water and String Algae. Used only in fountains and ornamental ponds with synthetic liners. Can be used with plants and ornamental fish when used as directed. Do not use in ponds with invertebrates or crustaceans, e.g. crabs, shrimp or crayfish.

Benefits:

• Helps control Algae Blooms (green water)
• Helps control String and Hair Algae (spirogyra)
• Helps control Blanket Week (oedogonium)
• Bottle includes a convenient dosing cap

Ingredients:

• 
  
  Active Ingredients: Poly [oxyethylene (Dimethyliminio) Ethylene (Dimethyliminio) Ethylene Dichloride]: 5.4%
  Inert Ingredients: 94.6%
  Total: 100.0% Directions for Use:
  
  • 
    String Algae:
  • Dislodge string algae off stones with high pressure hose nozzle and scoop up with a fine mesh net or pond vacuum. Ensure the pond or fountain is well aerated.
    Dosage:
  • 10 ml (0.34 Oz) for every 120 Gallons of pond water.
  • 1/4 Cup (60 ml or 2.03 oz) for every 720 gallons of pond water.
    
    Dilute:
  • Dilute the proper dosage in a bucket of water. Pour diluted mixture into the pond or fountain evenly along the edge. Do NOT over dose. Treatment may be repeated if needed every 3 days up to three total dosages. Remove dead algae from pond.
    
    Warm Water Conditions:
  • Before adding algae control be sure to provide adequate aeration from a fountain, waterfall or air pump. Keep pump(s) running 24 hours a day when using this product, especially during warmer months.
    
    Note: Do not use in ponds established less then 3 months.
    Notice: This product contains chemicals known to the state of California to cause cancer.
    
    See Product Label for Full Directions and Warnings.
  
  
  Details
  Mfg Part #: 77187
  Brand Name: TetraPond
  Product Type: Algae Control
  Treats up to: 6,000 Gal (22,700 Liters)
  Bottle Size: 16.9 fl oz (500 ml)

 

[teeemkay]

I used the TetraPond algaecide that Big Lou mentioned and it worked fine for me, no harm to the fish or plants. As he mentioned, you have to follow the instructions EXACTLY--do not overdose the pond or try to experiment with the dosage. If you specifically use that Tetra brand, be aware that the measuring device is on the *top* of the cap, not the inside of the cap (you will OD the pond on chemicals if you use the inside of the cap).

It also helps if you pull out as much of the string algae as possible before you put in the chemicals. Within a week or two, things will clear up.