Strange algae in water basin

Good evening Professor,

I hope that you can perhaps shed some light on this problem.

This is not really to do with fish, but I am hoping that you might be able to help as this is to do with water and some type of algae.

Some background information:

I am currently visiting family in Namibia and my uncle showed me some very strange algae that is growing in two of the water basins. The basins are holding about +- 65 000 liters of water. The water stored here is for animal consumption.

I was told that the algae grows upwards from the bottom, then breaks off and floats on the top of the water.

Below is some photos I took of the algae

Photo 1 is from the surface of the water. The “blueish†areas is from CuSO4 (Blou viterjoel) that has been added as he was advised to add this and that it will kill the algae. This however has had no efefct as of yet.
Photo 2 is from the top showing how the algae grows on the sides and upwards from the bottom.
Photo 3 shows what the algae looks like when taken out of the water.

I apologize as this is a bit of a strange request but I am hoping that you can assist me on this one.

Kind regards,
Ernst Bleeker

 

Hi Ernst,

Before i even try to explain, can you tell me where you uncle stays in Namibia? I ask this because in some areas in Namibia you have very hard water, in other words water that contains enormous amounts of salts and this causes all sorts of weird algae to grow.

Kind regards,

Dirk

 

Good morning Professor,

Thank you for comming back to me on this.

The farm is in the north west of Namibia a short distance north west of a town called Omaruru.

I was also told that the lime (I think that is the word for kalk) content in the water is quite high.

Please let me know if you need any more information.

Kind regards,
Ernst Bleeker

 

Hi Ernst,

OK, this explains things exactly to me. The northern areas of Namibia have ground water that is very rich in calcium (kalk) and salt. The levels are so high that normal aquarium fishes would never survive in this water and even Malawis would battle.

This sort of high salt, high calcium water is an ideal medium for Spirulina algae and I would not be surprised if this is what we have here. It is perfectly harmless, and as a matter of fact if you were to dry it, if it is Spirulina it is highly nutritious and you could feed your cattle on it!

This algae grows under conditions of high sunlight which I can see on your pictures. Because spores of this algae blow aroung with the wind all the time, you can try to kill this algae with whatever you like, but it will start to grow every time again. As a result you can forget about chemical treatment of the water. What you can consider doing is getting some fishes from the Otjikoto lake near Tsumeb and putting them in there as they do eat algae. However, I do not know if the Namibian conservation authorities would approve of my advice here!

Now, and this is a very important point. My original degree that I obtained at university was a B Sc Agric, and I did courses in Animal nutrition and Animal Physiology, so besides my Biochemistry background I also have a specific training here. UNDER NO CIRCUMSTANCES SHOULD BLOU VITROEL which is copper sulphate be added to such water that is to be used as cattle drinking water. Copper sulphate is not immediately toxic to animals, but it can lead to sterility problems in both bulls and cows. How much copper sulphate was added to these basins? If it was a lot, say one kg, then I would even advise that they be emptied and filled again with fresh water, but under NO CIRCUMSTANCES should this stuff be used again.

I never thought I would be giving animal husbandry advice on a fish forum, but here we go again, what next please.....?

Kind regards,

Dirk

 

Good morning Professor,

Thank you so much for the information you shared with me and I apologize for asking for advice not pertaining specifically to fish.

I asked how much copper sulphate was added and it was about 1kg. About 40 000 liters of water has been replaced by fresh water since I wrote the first time. Unfortunately the basin cannot be emptied completely as water is a bit of a scarce thing in this area.

The are other basins on the farm that has a lot of "kurpers" in them. These fish have been in there for a number of years and has been reproducing quite well.

Would it be ok if we catch a few of them (I guess 20 or so) and put them into the problem basin?

Kind regards,
Ernst Bleeker

 

Hi Ernst,

Glad to have been of assistance. I understand the scarcity of water in these areas, and I think the important message is that one should not add more copper sulphate.

The kurpers idea is excellent because the Tilapia from Otjikoto are also kurpers in any case and these kurpers would certainly also eat the algae, so try that and see if this will improve things. An initial introduction of about 20 would be good.

Kind regards,

Dirk