I have a two acre pond that exists solely to feed my 15 ducks and geese.
I dont want any creatures large enough to compete with them for food
or want to eat the small hatchlings.. I am having a problem with
the string algae and looking for the best things to eat the algae.

According to my research there are some good creatures that subsist
on algae and thusly may provide good control.

The Zett's Nurshery and Hatchery catalog lists the following
as good algae eaters.

Channel Catfish
Israeli Carp (Cyprinis Carpo)
Japanese Koi
White Suckers
Fathead Minnows
Crayfish
Snails
Freshwater Clams

In my case, I do not want any fish that will grow large enough
to be able to or want to eat baby ducklings. That rules out
Catfish and Koi. I think the Crayfish may eat too many of the
plants that the ducks feed on. I'd like advise on whether minnows
would be good for this purpose or not. I have read lots of info
about the red and fathead minnows on linked websites but no
one mentions them as good for algae control as Zetts does.
Of Course Zettes is selling them. What say the experts here ?

I am definitely leaning toward the white suckers but
it might also be good if the minnows eat a lot of algae as
I believe the ducks would consider them as nutritious treats.

Thanks
in Atlanta, GA

My opinion is that you should attempt to create a balanced ecosystem. Trying to fight algae with some kind of algae eating fish alone is an exercise in futility as the fish will eat the algae, process it and create fish waste, which is fertilizer for more algae. One initial step would be to introduce plantings of a wide array of other plants to compete with the algae for nutrients in the water. Emergent vegetation, such as cattail, pickerel weed, rushes and arrowhead, floating vegetation, such as waterlilies, frogbit, duckweeed, water hyacinth, and water lettuce and submerged vegetation such as hornwort, anacharis, parrot's feather, and myriophyllum will help to create diverse plant communities to compete with the algae. These plants, particularly the duckweed serve also as food for your birds. Floating plants such as duckweed and water lilies also help to shade the water and deprive algae of light. Water-shading chemicals that dye the water a dark color will also block light form penetration into deeper layers.

Remember, too, that ducks and geese are notorious for creating large quantities of fecal waste, which will invariably create enormous algae blooms unless there are very large quantities of other plants. Plant, plant, plant!

You should also consider some form of aeration, it be form airline bubblers beneath the surface, floating fountains, or artificial waterfalls. This will encourage the growth of beneficial bacteria to create nitrogen cycling.

Creating a balanced ecosystem will take time, but it is the real solution to algae in the long run. There is no really permanent, simple shortcut to algae control. You can use algacides, but these are not necessarily in the best interests of your ducks and ultimately the dead algae will decompose and cycle their nutrients into more algae.

Don

I totally agree with Don. Plant, plant, plant! And aerate!
Check out http://www.fishpondinfo.com/plants/plant.htm
http://www.fishpondinfo.com/plants/algae2.htm

In the interest in trying to give a complete answer, here's what I think about the "algae-eating" animals that you mentioned.

I don't think koi would eat baby ducks. But, they also won't be eating any hair (string) algae.

Channel catfish are mostly predators and would also ignore algae.

I'm not sure what "white suckers" are. Maybe they mean white amurs? White amurs or grass carp are good at eating algae and all plants in the pond so they'd compete with the ducks for food. They are generally genetically altered so they cannot reproduce which is a good thing.

Fathead and rosy red minnows ( http://www.fishpondinfo.com/rosies.htm ) are great but they won't really eat algae. The ducks would eat some of them.

Crayfish also aren't great algae eaters.

Clams are filter feeders and will eat suspended algae but not attached algae like hair algae.

Snails are probably the best algae eaters in your list. They won't harm the ducks; the ducks may eat some of them. I suggest Japanese trapdoor snails and/or black ramshorn snails. Now, snails are going to prefer the good attached algae not so much the hair algae. In fact, nobody really likes that (only rosy barbs that I've found but they're tropical). Who can blame them!

I have a 1/3 acre pond that is just a pond no filter no pumps no nothing ihave Koi, bass and Blue gill.

i put in Grass carp aka White Amour they are steril eat only vegies and get big but very shy i always see them and they are a great addition to the pond. To big to be eaten and eat all the vegies i have 2 and they always seem to be together I want to get more this summer.

Sorry, I neglected to mention that I have covered the banks with
Water cress and have anacharous/elodia in the water along with
hyancynth, and duckweed. Yes I agree whole heartedly about
the complete eco system and am trying to be selective and
as much as possible only have plants that the ducks like to eat.
Also I have a few water lillies.

I believe some of my plants are so called oxygenators
and thusly I wont have to have aeration.
Koi can get big enough to grab baby ducks and we know
that is true with big mouth catfish. The sucker fish have small
mouths for cleaning algae off the bottom and off rocks and
pebbles. There has to be something that likes string algae
that wont eat the better plants first ? ? ?
From what some of you have said, Zetts advertising
is misleading or false although no one specifically mentioned
the isralei carp as a special species.

I've been reading a lot about Koi Clay (Calcium bentonite). It is used to replace minerals and trace elements needed for healthy koi, but it is claimed that it will also kill string algae. Has anyone tried it for that purpose? If no one has tried it for this, I think I might get some and try it before I physically remove it from the water lily containers when I repot. Any thoughts?

Don

I haven't heard that Don. I add koi clay to my 1800 gallon pond. It has string algae but not much and mostly just in the spring.

Submerged plants are also called oxygenating plants. Anacharis is an example. The problem is that they produce oxygen during the day in the sun but actually use oxygen at night (giving off carbon dioxide). That means, if you have a pond with way too many submerged plants, aquatic animals can actually suffocate over night. That's not an issue for the ducks since they breathe air. But, the pond will be a lot less stagnant (in other words algae growing with film on the water) with some water movement. In larger ponds, that's best done with an aerator.