http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=201295&page=1



How in the world can adding more waste to the ecosystem increase carrying capacity? The good bacteria colonies have to increase in size to break down more waste. This takes time. Fish waste breaking down releases ammonia, one colony of good bacteria convert the ammonia to nitrite. Both ammonia and nitrite are toxic to fish. Another colony of bacteria breaks the nitrite down into nitrate aka fertilizer. While all ponds have these colonies of bacteria they are competing with plants for the waste nutrients. Its more than likely water plants or plants growing around the pond uptake a good portion of the excess nutrients in its purest form ammonia. In my experience over stocked aquariums that are overfed are more likely to experience a crash of the good bacteria leading to fish death. These good bacteria do best in water with high levels of oxygen so aeration helps a lot. Most ponds don't have a steady overflow simply because they barely have enough incoming water to account for evaporation. Only during severe rain events do most ponds use the overflow.

Understand its a balancing act. More waste equals more plant growth. Plants plus aeration supports good bacteria and your fish. In my experience bad things happen when you push the limit by having too many fish and overfeed them.

I will let ewest defend Parts 5, 6 and 7 first since those were his comments. Stay tuned.

Mr. Cody....I am by no stretch a pond expert. However I have a good knowledge of how biology works concerning fish.

My goal is to stimulate interesting conversation/debate on the subject. Most aquarium folks could care less about the science. They bore me!!

BTW I have adopted your concept of not stocking your top end predators until they can go to sleep with their mouth open and wake up full thought.

We have always had a tropical fish tank in the house when I was younger. I worked for my uncle when I went to collage for my room and board by washing and feeding angel fish.

Now that I have the money and the land we have built our biggest fish tank yet. Our pond. This is how I look at it.

Cheers Don.

Just curious as to whataquarium owners consider to be the lbs per gallon of water capacity of your fish tank?

aww heavens. I'm no expert at anything anyone here cares about, but I can read English. He didn't say more waste increases carrying capacity. He said a larger waste processing facility allows the ecosystem to process more waste thus maybe more fish. Bout time to pack up for my trip to the pond.. see y'all next week.

Don? Any video of you washing those Angelfish! I always thought they were pretty good at self-cleaning!!!

I respectfully disagree concerning comment #5. Have a good weekend!

Good stuff Rainman!! I am curious as to what substance he washed them in?

FF, perhaps your definition of "Carrying Capacity" is different. Typically, Carrying Capacity pertains to the average pounds of fish any given BOW can support, NATURALLY. That means, non-aerated, unfed, and unmanaged. Any human intervention changes "carrying capacity' toward more maximum socking densities, BOD capacity, management capability and more, but it is no longer related to the "carrying capacity" of the pond once it becomes an unnatural assistance....


Every natural pond has a constantly changing carrying capacity based on temperature changes, nutrient availability, BOD changes during different seasons (temp changes) and an almost infinite list of variables.

I routinely maintained my Blue Tilapia fingerlings in aquariums at a stocking density exceeding 300 inches per gallon.....I also used bio-filtration that could handle the load, diffused pure oxygen and multiple solids filtration units that often required cleaning twice daily.....When a power outage hit, I had to move fast to hook up a generator!!!

Point 5 refers to the fish being fed.

My definition of carrying capacity is the maximum amount of fish the pond can hold before crashing. You are right about many variables coming into play. Lets say you stock a pond with plenty of vegetation with the maximum number of tilapia the pond will hold once they are ready to harvest. The fish grow to a nice size eating all of the vegetation killing their oxygen supply. The fish die because they got bigger and in the process took away their main source of oxygen.

I bet you did!! Back in 2011 we were without power for 6 days. I didn't have a generator. We went and stayed with some family until we had power again. I had lots of fish tanks going at the time. Believe it or not not many fish died because they were stocked lightly. However they were never bred again and some seemed permanently stunted. The lack of oxygen didn't kill them but for all practical purposes it might as well have.

As for the highlighted comment in red...NUTRIENT is being added, waste is an inevitable by-product of the addition...the fish weight WILL increase...not from waste as you said, but added nutrient...

Blue highlight...The part leading up to the highlighted comment is accurate. Bacteria colonies, collectively called "beneficial bacteria", digest the waste, converting it first to ammonia, then to nitrite and eventually nitrate, which brings me to a wholly inaccurate claim wich I highlighted...there is NO competition between plants and bacteria!

The green highlighted comment...You were right in there being a "balance", but there is no competition. Like the fish rely on plants for oxygen and an edible form of nutrient, plants rely on bacteria creating a consumable nutrient and the bacteria rely on the fish for their consumable nutrient...

Any comments about needing more bacteria to process more waste could also be debated to be moot. Bacteria colonies will not grow and expand unless there is waste for them to consume.

Like plants and fish, bacteria colonies cannot magically grow and expand unless there is food to grow on.

Affecting one will always affect the others in this simple, 3 part circle of plant, bacteria and fish.

The perfect example is cold weather where bacteria colonies die off due to fish not creating waste due to plants dying off from reduced sunlight during winter....and a ponds natural "carrying capacity" drops in direct proportions.

Some bacteria use ammonia. As diverse as bacteria are I suspect that some bacteria species also use nitrate as a food source. Some types of plants (esp algae) consume ammonia directly, thus they both use ammonia which by my definition compete with each other for ammonia. If some bacteria are able to utilize nitrate then they too also compete with plants for nitrate.

Your explanation is correct.

I confused things by saying aquatic plants can use ammonia. Its been about 10 years but I dabbled in hydroponics. During that time period I vaguely remember reading about some terrestrial plants that actually preferred waste in the concentrated ammonia form.

My apologies for the confusion.

Edit: It had been so long since I read on the subject that I honestly couldn't remember if the plants were aquatic or terrestrial.

FF you are correct some plants can absorb and utilize ammonia directly from the water.

I'm not sure this is completely correct: ""The perfect example is cold weather where bacteria colonies die off due to fish not creating waste due to plants dying off from reduced sunlight during winter....and a ponds natural "carrying capacity" drops in direct proportions.""

Do the bacteria really die off in winter or do they go dormant or both. If lots of bacteria are dying in winter (39F) is it because fish are not creating waste or is it because of the cold temps? I propose it is the cold temps because there is plenty of waste in the form of bottom sediment / muck. At least my pond has plenty of organic muck. Plants do not always die off in winter especially in ponds where there is little or no ice cover. Trees and many other perennials do not die in winter, they go dormant due to cold and reduced day length. In addition some forms of algae (usu planktonic setenotherms, stenothermic) thrive and actually form big blooms that color the water during winter under the ice in 39F water. Research Planktothrix rubescens for just one example.

Actually plant life does both take and consume oxygen. However, in a properly maintained pond(as versus an aquarium)the main sources of oxygen are sunshine, wave action(wind) and phytoplankton.

It is believed that a bacteria exists that consumes nitrates. Much time and energy has been spent in the aquarium hobby trying to develop something to reduce nitrate. The best that exist aren't real effective. In the aquarium world it is best to do 25% water changes weekly to remove nitrates. Partial water changes is work. Apparently Plants/Algae are much better suited to use the nitrates than this particular strain of bacteria.

Natural aquariums do exist. Bulbs in the right spectrum to replicate the sun. One airstone to agitate the surface for gas exchange. Typically heavily planted with shrimp and some fish. Green water is considered undesirable in a natural aquarium.

I do have a question for you pond pros? Does the recommended amount of aeration in a pond effect getting a good algae bloom?

Bill, I agree that there are many holes in my example if one wants to look closely. And as Dave noted, plants also respire. Part of my point in trying to bundle the discussion into 3 basic, or general parts really can't be done because of the infinite interactions possible. That is also why I once said a single mold spore or bacteria entering a pond forever alters it's development. No matter how hard we try to control an environment, nature will do it's own thing.

I do know that in my bio-filters, bacteria dies and grows nearly as rapidly as food (waste?) is available or consumed. Does it go dormant in cold weather? Possibly, we know many fish metabolism's slow.

In my fluidized sand bed filters, I could feed 2 cups of fish food to my fish once weekly and within an hour, ammonia would spike. In another hour, bacteria growth on the clean sand substrate was lowering levels rapidly. As ammonia levels began returning to near zero, light, visible clouds of bacterial "slime" would begin to be spit out of the sand filters. I can only presume it was due to a lack of food. My tilapia would hover around the discharge water gobbling them up. But, Tilapia help reduce muck in ponds by aerating detritus and eating the digesting bacteria.....

The good aerobic bacteria colony will adjust its size to the food (ammonia and nitrite) and the availability of oxygen. In a pond in the north that the water gets down into the 30's in the winter the fish's metabolism slows to the point that they are using fat reserves stored in the liver to live. The colony of bacteria adjusts to that level of waste produced as it is the limiting factor. Once the Spring thaw occurs and the fish begin actively feeding again the bacteria colony increases in size as food (ammonia and nitrite)become available.

If the bacterial colony dies it takes 2-4 weeks to establish itself again. During this period you would have ammonia and nitrite spikes probably resulting in some if not all of the fish dying.

If food and oxygen are available the bacteria colony will live through the cold.

*EDIT* The cold water algae is probably getting its food in the form of nitrates from the colony of aerobic bacteria. From what I know nitrates and phosphates are what fuels the algae.

Mr Cody...Do you have an opinion on my aeration effecting algae bloom question?