Why Do I Get Blue Algea in My Fish Pond After it Rains?

Aeration

I don't have any ponds here in Arizona, are yours in NY?

I'm in awe of your accomplishments.

You do know that any bozo can carry concealed here in Arizona, with NO QUALIFICATIONS, other than the price of a pistol.

GA old salt. You are correct stating the low pH of rain water. It is often very low. There is also an abundant of phosphorous (P) available in decomposing vegetation like leaves. Every time it rains it will wash a little of the trace nutrients like P, N (Nitrogen), and organic carbon (C) into the pond. That stimulates the algae. Bottom feeders like Carp (gold fish) feed on the algae produced while mosquito lovers tend to feed on well..everything but algae. It does not take a lot of CNP to cause growth of algae and these algae can have their own toxins.

Acid rain runoff can release a lot of metals into the water including mercury, copper, iron, etc. Many metals can be toxic to fish. OP may want to assure the area around the pond is clean or lined with some base material like limestone. Limestone has also been used to buffer lakes affected by acid rain. I would suggest OP follow you advice.

Kevinm-

Yes, acid rain is a much bigger problem than most people, including engineers and scientists, realize. My person experiences were mostly with a 30,000 gal in-ground pool. Every time we would get a substantial rain I would test the pH. It would go from 7.5, where I maintained it for Chlorine retention, to the range of 5.0 to 3.5. Had to dump a lot off soda ash during a season to boost it up. Fortunately the chemical plant I managed had many bags of it that were caked hard. I gave it to anyone with a pool who wanted some, including myself. Drop a cake in the skimmer and the cake is dissolved overnight and the pH is raised.

Thanks for the GA. Your post is very explanatory and informative. Hope others appreciate it as much as I do.

Good Luck, Old Salt

Well the goldfish are algae eaters....So I would just plop some in with the mosquito eaters....an overabundance of algae growth is usually caused by nutrient rich environment, which can be caused by overpopulation of fish or fertilizer runoff...I would just balance the fish population with a variety of algae eating fish....Blue-green algae grows everywhere there is freshwater and is to be expected....When and if it blooms, it can have a tremendous growth spurt at the time....but the right mix of fish will usually eat it as fast as it grows under normal conditions....this can be controlled by feeding the fish yourself at times, and holding back when algae becomes a problem, forcing the fish to eat the algae.....

I don't mind the green algae, but the blue (tending towards turquoise) is bothersome. I have about 150+ Mosquito fish in there and they can't seem to keep it under control. I've only encountered this in the goldfish pond once, and skimmed out the floating blue algae. I have read somewhere that it can kill the fish. What are your thoughts on this?

Yes the blooms can be very toxic not only to the fish but to you as well....but if the fish appear to be ok at this point, then it's probably not effecting them.....There are many cyanobacteria types and species, and some can get pretty weird...but most are harmless to the fish, and serve as an excellent food source.....

Mosquito fish do not eat algae. They eat insects. They will never control the algae in their pond. You may be overfeeding them leading to high levels of nutrients in the water fueling the algae growth. Draining half the water in their pond and refilling with fresh water may help. You could swap some fish between ponds. that should help.

High levels of Nitrogen and Phosphate are know to cause algal blooms in ponds best bet find something that will help clean out your ponds. Tilapia are a good example or carp not sure what will get along with your fish. The blue algae only has toxins from one species you'll need to test for it. Its not know to harm fish but could harm other animals drinking from the pond. There are many FAQs on line from different states concerning this subject.

Blue algael blooms after it rains tending to turquoise....send a picture..Look at the algae inder a hand lens or better yet a microscope..sounds fascinating..Can you share a photo at various magnifications..??Take a sample to a local university or college with a biology faculty..Turquoise algae may have huge potential me thinks..:)

Take and sell the blue-green algae/cyanobacteria for oil production. Call up saphire energy and tell them you want them to cook it to bio-crude. Can you say $$?

On a more serious note: (1) you can keep the fish segregated and ride the "blue algae" by circulating water between tanks, so the goldfish will keep the stuff consumed. Keep the tanks well aerated, if at all possible.

Algal blooms after rains suggests (1) strong lightening storms as in Arizona may produce higher levels of fixable nitrogen in the rain., (2) higher levels of available carbon dioxide for plant respiration (due to a shift of pH to a lower value).

You might what to eliminate the source of the pollution along with the pH buffering of the water. Blue green algae is a very early life form it can photosynthesize but it can also attack other life forms just like a bacteria. You may be getting rain run off from the land around the pond. If so, I would try to prevent this from occurring. This is not really possible if the pond is at the bottom of a depression. You might also want to top off the pond with a garden hose, a little at a time. You do not want to change the water chemistry too quickly so you do not kill the fish. The fish may not like the chlorine. The additional water will dilute the pollution and the runoff may not all enter the pool. If the pond is not in the lowest part in your yard, some may continue towards the lowest spot. Phosphates have been banned in fertilizer, detergents and probably everything else a few years back. I bought a case of cascade after the formula was changed. We use that to clean the good dishes we use for holidays.

I live near a mile long lake. The lake has warning sings concerning the blue-green algae. The signs warn people from coming in contact with the water. The algae is not a curiosity here. Our lake suffers from an over population of wild life. In our county there is a ban on hunting. Years ago the lake was deemed polluted having a high population of echoli. There was a hunt for how raw sewage was getting into the lake until is was discovered the strain did not come from humans but deer. Then a law was passed not to disturb Canadian Geese. Now there are thousands of geese on the lake till it freezes.

I will refrain making a comment about this.

Since these are raised ponds, and I don't fertilize my trees, I think I can rule this out. However run-off from the leaves could be a factor.....yet there are the same trees in the area of the second pond. They are less than 3 feet apart. The water in the Goldfish pond has a stronger urea content as the Goldfish are "dirty fish". I have, since, replaced about 80% of the water in the first pond and noticed how turquoise the water pumped out was. After lowering the depth of the water and exposing the rocks, etc, the blue algae had died off to a large degree. Whether or not it will return with such a vengeance is in question. My concern was in that it happened after each rain storm (of which we don't have much in Phoenix) and I can only attribute it to the addition of the rain itself. Granted, the Goldfish didn't get it this time, but, again, their water is always full of excrement.

My thanks to everyone who posted a response! Sorry that I don't have the microscope ad other tools to test the blue algae, but since my house burned down a year and a half ago and whatever survived is in storage, I'm limited in what I can do.

Have you considered calling your local extension agent? (Most counties have an agricultural extension service agent who is there to help with just this type of situation as well as other agricultural problems.)

When ponds have algal blooms, generally they will suggest getting a few bales of barley. By throwing a few bales (dependant on volume of the pond and severity of algal bloom) as the barley breaks down (rots) it releases hydrogen peroxide into the water which does not hurt the fish provided you don't over do it. The hydrogen peroxide does have a negative effect on the algae as it will kill it or at least control it. You may also google "barley straw hydrogen peroxide" to find out more. If you have trouble finding barley straw, this same search will let you know where you can get other products based on the same barley hydrogen peroxide as a substitute for the barley straw (which is your cheapest remedy).

If you have no agriculture extension agent in your county, get ahold of the university in your area which has an agriculture program as they will generally be able to help. Most states provide assistance by way of the extension program.

Who'd a thunk our main beer product could have such uses. Thanks.

I have had some experience operating a pool with sodium percrbonate This is a product that uses hydrogen peroxide as its active ingredient and is found in most eco friendly cleaners. About 3 kg of sodium percarbonate/100,000 liters will work to control algae, fungi, and molds in pools. The dosage level ~100 mg/L would not harm humans and was based on eye response. I know some users who maintained bait tanks with minnows and were happy with it. I suspect it will be effective in ponds and is easy to maintain and distribute. The dosage will decrease with time and can be topped up as required. My pool would run about 2 weeks without any further action.

A caution, peroxide will decompose to form chemical available oxygen. The oxygen will combine with itself to form oxygen gas (O2). That gas will attach to vegetation decomposed on the bottom of the pond and likely float it to the surface. That can be both an advantage and a disadvantage. Good in pools where skimming is practised but a pond may be a problem. The floaters will sink again as the oxygen gas is used up.

Not for pools, but a product used (sometimes) in cooling towers and ponds for algae control is terbuthyl azine. Actually, this product does not harm fish, but shuts down photosynthetic organisms. Another idea to check out with your local ag experts, especially if anyone in the Phoenix area is doing aquaculture fish production. Don't ask me where to obtain this product, as it has been a while since I needed it.

Found this it seems to cover everything.....↓

http://www.gotalgae.com/algae_solutions.htm

Good link. They appear to have a passable idea what they are talking about.

Research actual shows the pH levels lower then 6 starts to kill of blue algae increasing the toxicity by increasing the pH above 8 will cause blooms to acure. When I was in college we did an experiment on a lake that was dying in the Pocono Mt. No algae colonies where found and fish counts where very low pH level was around 4-5. It was a while ago and I won't bore everyone with a long story. We add baking soda during winter on the ice. By late spring we ran into another problem an algae bloom of blue algae pH was around 8-9.

Your experiments were correct. Low pH will inhibit B/G algae. However, in a poorly buffered pond pH swings can be large and rapid. Old salt suggested testing and logging of the pH over time. There are other algae that can be found at lower pHs but not the B/G type. When there is a heavy rainfall, it is the wash of nutrients that will cause a problem with algae. The pH will rebound as quick as it dropped and once rebounded the B/G algae can bloom. The use of a carbonate will buffer the pond and help prevent the pH swings. Limiting the input of nutrients is the most important aspect. Algae will grow in proportion to the nutrient levels in the pond. However, limiting metals into the pond is also essential to protect the fish. I wonder if the pond has alkalinity sufficient to buffer. Some of our northern lakes have very low alkalinity and are stressed seriously by acid rain. Mercury in fish is common in larger fish from some of these lakes.

http://en.wikipedia.org/wiki/Blue-green_algae

http://en.wikipedia.org/wiki/Blue-green_algae
This article doesn't explain how to test for toxic blue-green algae. I would appreciate as simple an explanation as possible. I don't have a lab, so what would I need in order to test for toxins?

"There currently is no rapid or easy test". But University of Helsinki has a technology transfer out that should result in a user-friendly test.

The blue-green algae testing kit developed by VTT and the University of Helsinki is like a miniature laboratory. The device is the size of a thermometer, and it contains antibodies that react to any toxic bacteria found in a water sample. The test reveals in minutes whether the water sample contains toxic blue-green algae.

http://www.vtt.fi/news/2013/18062013_waterchip.jsp?lang=en

Otherwise, about half the cyanobacter blooms will be toxic, so flip a coin, or send a sample off to University Laboratory (University of Arizona Biological Sciences is my guess), or try http://www.envirologix.com/artman/publish/article_67.shtml which is a new test kit that takes about 30 minutes to get results. Be careful when sampling by wearing gloves. Hach Co. (Loveland CO.) offers a BART test for this also:

http://www.hach.com/bart-test-for-blue-green-algae-pk-9/product?id=7640250879

Have you tried and fish friendly algaecides there are a number of algaecides on the market that may meet your price range and ease of use.

Any time I have attempted to use "fish friendly" algaecides, I have lost my fish, too. Seems they aren't all that friendly to ALL fish.

Which ones? Do not use copper sulphate, as the general biotoxicity is too great, and people generally tend to overdose with copper sulphate anyway. Good luck with whatever course you decide.

You could use a local water testing lab might be cheaper plus they are the experts. Local one in Phoenix I use is Test America, but there are others just as good. Depending on how much you want to spend you could have a full spectrum chemical test including the species ID and toxic level if any.

Yikes! Measure the alkalinity and measure the pH. Easy strips are cheap and readily available.

http://www.dailymail.co.uk/news/article-2187284/The-poison-Blue-Lagoon-It-look-inviting-water-toxic-bleach.html

That way the OP has a comprehensive look of what her ponds have in them. Including species of algae pH, N, P, Alkalinity, toxicity, plus other minerals and nutrients levels in the water. From there she can take the information and do some research on what can be done to remove the algae or live with it. she can also take the data and check with any number of local experts. At this point we (us and the OP) have limited data to make any decisions. Another way to go with my pool at start I take a sample and bring it to the local pool store and they do a free test on your water to determine what needs to be done. A possible way to go is check with a local outdoor fish expert he may be able to help with a similar services. Here is a web site that might be of use so you can talk to the experts. WWW.phoenixponds.com

Thank you! All of the information has been very helpful!