# Why Dead Leaves?



## mordalphus (Jun 23, 2010)

I buy my leaves from a family wholesale operation and they do wait for leaves to fall. Actually what they do is harvest different groves at different times to always have new stock available at all times. They then steam the leaves to kill insects and fungus and then flatten and dry them. 

An over abundance of sugars, and nitrogen, and potassium and chlorophyll, etc can cause bacterial problems in your tank and upset a delicate balance. You can attract fungus or algae problems as well. It's best to not leave something to rot quickly in your aquarium.


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## thelub (Jan 4, 2013)

I'm no pro, but from my understanding, we use the dead leaves for the tannins which are a natural antibiotic and acidifier (is that a real word? lol). Like Mordalphus said, live leaves that are pulled off the tree are full of all sorts of things that aren't beneficial for the aquarium.


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## ljapa (Jul 23, 2013)

There's a great thread on leaves with some of your questions addressed going right now

http://www.plantedtank.net/forums/showthread.php?t=509977

I've only ever used oak from the back yard. With a few exceptions like mulberry, the shrimp aren't eating the leaves. They're eating the bacteria/fungus/algae that grow on the leaves. Since leaves generally don't decay until they are dead, I'd assume that leaves that are harvested live still have chemical compounds in them to retard growth of bacteria that are going to consume it. 

Besides that, I'm betting that a leaf with its waxy coating more intact will take much longer to become waterlogged and sink. Dry leaves don't take long.


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## shrimpo (Aug 2, 2009)

Old McDonald said:


> Dead leaves have had everything returned to the parent plant.


And that may include toxins, metals, pesticides...that the tree absorbed through Phytoremediation, I am not 100% sure about the previous statement.
In the shrimp natural habitat dead leaves fall into the water, the microorganisms start breaking down the dead leaves, every slice that the shrimp pick up from the leaf has thousands of those small critters (food), so it doesn't matter if there is nutrients in the leaf or not.
I could be wrong but I just want to share what I think.


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## Aquasapien69 (May 7, 2011)

+1 on What Shrimpo said... Except for the medicinal properties from the tannins, the dead leaf is the substrate on which other micro-organisms grow. It's like taking a handful of hay or straw and placing it in a bucket of water and before long you get a plethora of microbes inhabiting the water. Whether or not the shrimp "eat" the dead leaves is debatable to some, however it does seem that the microbes growing on the leaves and the tannins are why we use dead leaves. Green leaves....or green leaves dried...besides those that are eaten directly by the shrimp (ie mulberry, nettle, spinach, etc.) would just rot and cause water quality issues for us.


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## plantbrain (Dec 15, 2003)

You can state the same things about driftwood.

Some have taken to selling old bark from various trees as shrimp food etc, as they last longer, look nicer and can be used for many other things. They also have tannins and we can obvious show plenty of examples of shrimp gnawing on driftwood. The evidence based on observation is identical to all the leaves. Tannins and a substrate for periphyton to grow on, which in turn, the shrimp feed on. 
Driftwood commonly gets coated, but a shrimp tank usually picks and cleans the wood, no fungi appears. I know. I've done it many times and cure wood this way for smaller tanks in some shrimp tanks in my garage. Whether or not the wood was sterilized, this will not stop aquatic fungi, unless you plan on full sterile technique, which no one in this hobby is going to bother to do.

You can steam, you can try various leaves, and various ages after being trimmed off the trees or fallen off. Same with wood. Many boil their wood, mostly to water log and leach some of the tannins out. You can also use peat and this has a long long history by aquarist and planted tanks. 

pH in peat bogs are very low, anoxic and low nutrient. 
Which is why nothing or little breaks down in a peat bog, there's no bacterial or fungi activity.

As far as a reference: 
The Ecology of Humic Substances in Freshwater 

is a good resource for looking at tannins and their impact on natural aquatic systems. Most of the leaves or things folks add to their aquariums are done out of simple local resource availability: when in Rome, Eat pizza, or when in Portugal, eat Bacalhau and Chicken, maybe some grilled sardines. 
Adding peat to sediments was suggested going back to at least the 1950's. 
I add driftwood since I use and have a lot, the shrimp selling tanks and culls do much better, much higher breeding production and nicer color than in the tanks without plants or wood. I have 5 tanks out there and 2 tanks have no light, so only wood/no wood. I've removed the wood, only to find much less production. So the treatments appear to work. I do no think the type of leaves or wood is critical however. Moss also is something that shrimp do well with, likely due to the periphyton growth and the high surface area of moss relative to say, a Sword plant.

I would look at more general trends and see what common factors tie them together. Observations are good, but you need support(much more) to say that Kappa leaves are better etc than Oak leaves. No one has convinced me even remotely that they are.


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## Art by Stef* (Jan 27, 2013)

Basic building block. Live leaves do not just fall off a tree into a creek, lake, or pond.
The dead feed microorganisms and fertilize, which feed lower life forms, which feed
the fish, and so on, and so on...

Just as you would not put green wood in a tank.

Observation: I use sun dried banana leaves from my backyard tree, IAL, and alder cones.
I've had most luck and notice best results with the banana. I don't know how
the IAL and cones are processed, but the banana leaves just get a quick rinse before I put them in a tank.

-Stef*


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## thinBear (Dec 16, 2011)

maybe dried leaf are easier to be stored/preserved/transported for a long time, and it become a habit among the hobbyist, more like a human factor


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## lochaber (Jan 23, 2012)

I think one of the things that often gets overlooked when talking about foods and fertilizers and such, is that in an aquarium, everything is in the same medium. We can't really separate the food from the substrate from the water.

Some materials may be undoubtedly more nutritious or better fertilizers, if that is the only angle being considered, but they may render the water uninhabitable, or more favorable for unwanted microorganisms, etc.

I believe a lot of the stuff that aquarists have learned to use are items that strike a balance - they can provide increased nutrition, fertilization, etc., without immediately ruining the water or causing a suffocating bacterial bloom or something.


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## Old McDonald (Dec 27, 2013)

Many thanks for the quick replies. I am grateful that people take time to try to answer my curiosity. I had read the other thread, but it does not address the question. 

I have few interests outside farming and gardening, but I am deeply curious about all sorts of farming, and that is what you are doing, raising, breeding, and some are selling, livestock. It does not matter if you only have half a dozen shrimp in one tank – you are looking after your livestock just the same as me with 100 pigs in England, 400 cattle and 1500 sheep in Australia, 2000 hens in Scotland, or a dozen goats in Portugal. These were not the only enterprises on the farms, but still, you are a farmer – a shrimp farmer.

There are things to be learned from all branches of farming that can be applied to other branches. The reason I am so keen to follow this through is because of my use of mulches for plants. We have hot and dry summers here and mulches help to ameliorate the ground temperatures around plants. I am increasingly using cut comfrey leaves for this purpose and am working towards providing two comfrey plants for each of my almost 500 olive trees. Whilst I found out about the use of dead leaves by chance, I have spent a lot of time in the last 10 days or so (almost constant rain so no outside work possible) trying to find why shrimp farmers use fallen dead dry leaves (DDL) and not harvested dried leaves (HDL). 

If there is a compelling reason to use DDL, would that reason also apply to my mulching of the olive trees? You might think that this forum is a strange place to be pursuing the question, but in turn I think you might be able to teach the world of mulchers something. Alternatively, the answer might be that there is no reason not to use HDL instead of DDL.

I also did some research on periphyton, taking the view that whilst some animals may consume the leaves, many, including the very young, were grazing the periphyton. I noted that periphyton production was often restrained by limitations in the supply of Nitrogen(N) and Phosphorus(P). Suggesting that HDL would be a better source of nutrients for the periphyton. Furthermore, that in streams where flood waters have removed the periphyton it recovers much more quickly in water with better nutrient levels. Also that, as posted by plantbrain, I have not seen anything to suggest that one species of tree is better than another at providing the periphyton for the shrimp. Nor, indeed, that DDL are needed to produce periphyton. On two of my farms the house has been situated within 50 yeards of a river. I have also been an angler for about 60 years. I know that summer storms can cause immense numbers of growing leaves to be knocked off trees and into the river.

Leading on from the periphyton research I considered the role of mycorrhiza underneath the comfrey mulches. In much the same way as the periphyton use the leaves, some mycorrhiza can supply available P (a very immobile mineral and often unavailable) to plants from leaf litter on the surface, rather than take it from the soil. The leaf litter is normally naturally fallen leaves. 

As for possible contaminants of the water when using HDL, I cannot find any evidence to show that the levels of Carbohydrates, N, P, or K in leaves would cause any problems in your tanks. In my OP I posted that I was familiar with the use of chemical analysis of leaves. N levels could be up to 2%, P unlikely to be more than about 0.2% and K a maximum of 1% even on heavy clay soils that release K. Total carbohydrates are somewhat higher in fresh leaves, but the weight, and it would have to be water soluble carbohydrates to have any effect, is miniscule. Chlorophyll is the green pigment in the cyanobacteria in periphyton, also the chloroplasts of algae and plants. It is not soluble in water so cannot be a problem. I weighed some Loquat leaves last week, because they are the heaviest I have. I chose the biggest leaves I could find and they averaged out at 4g per leaf, including the short leaf stalk, for a freshly harvested leaf. Dried they will weigh about half that. At the levels being discussed for inclusion in a tank, there is no possibility of leaves providing excess amounts of nutrients to a tank. Not all the NPK is available, nor even soluble in water, when the leaves are introduced. But some of the periphyton organisms can use these insoluble nutrients. The slow breakdown of leaves in the tank, is surely a good reason to use them, not a detrimental factor. 

Perhaps I should not have used the phrase “everything returned to the parent plant”. I was thinking useable plant nutrients, not everything held in the leaf tissue. I believe we all accept that some tannins are not taken back into the roots. Similarly, heavy metals are not either. Consequently, leaves from any plant used in phytoremediation, at whatever stage of the leaves’ life or death, will contain those heavy metals accumulated in the growing leaf. Nobody would knowingly take the risk of using leaves from a plant that had been used as a phytoremedialist. 

I still cannot find anything that says HDL should not be used, but I still do not know which is best for shrimp farmers and mulch users – HDL or DDL. Maybe there is no difference. 

I appreciate that forum users might not want to continue responding, and I again thank those who have done so.


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## shrimpo (Aug 2, 2009)

Old McDonald said:


> I still cannot find anything that says HDL should not be used, but I still do not know which is best for shrimp farmers and mulch users – HDL or DDL. Maybe there is no difference.


 Our shrimp tanks are small enclosures, any sudden change may affect the shrimp and other microorganisms. If I ever used HDR I will have to do small daily water changes until the leaf decompose.


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## mordalphus (Jun 23, 2010)

I do believe there is some leaves better than others, but not because of what they contain necessarily. If You're using the leaves as a surface to grow bacteria and microorganisms, then big thick leaves will last longer in the aquarium and generate more food. If you're using a soft leaf like maple, the leaf will disappear in very short order, possibly being eaten by the shrimp themselves. 

If you are feeding a leaf as a direct food source, it's best to go with a fresh leaf, popular options are spinach or mulberry which are high in calcium. 

But as for your skepticism about fresh leaves not disrupting the delicate balance of nutrients and bacteria in an aquarium, I suggest an easy experiment. Put a handful of green leaves in a bucket of water, and a handful of dead leaves in a bucket of water and leave it outside for a week or two. 


I can tell you right now what happens, because it happens every year in my 250 gallon stock pond. In the fall the tank is full of dead maple leaves, and the water is crystal clear. Tea colored, but clear as a bell. In the spring and summer when BlackBerry clearing and general yard work, the pond gets a dose of nice green leaves and grass. And the water goes through a few cycles, first it gets cloudy, then it gets nice and green! I usually dredge it out and flood it once August rolls around and it clears up til the following spring. 

Could just be BlackBerry and grass, but I've had the same thing happen in an aquarium that had uneaten spinach do similar things, so I pull out green leaves now when they've been in the tank for a day.


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## Old McDonald (Dec 27, 2013)

Thanks again, my post #11 did not appear until 8th January my time, late on the 7th for some readers.

I repeat, I am not talking about fresh green leaves, but a comparison between dried and naturally dead leaves to grow periphyton, or in my case mycorrhizal organisms.

Again though, thank you all for having thought about my question and taking time to respond.


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## mordalphus (Jun 23, 2010)

But isn't the only difference between fresh green leaves and dried green leaves the moisture content? 

Also growing a fungus and growing microorganisms is two different things. And mycorrhizal fungi benefit the roots of a plant, not the soil topping. So in order for them to benefit from the nutrients in the leaves they'd have to soak like a tea into the soil below. And I'm not sure if this would be beneficial during the winter (when mulching is traditionally done) because mycorrhizal fungus goes dormant just like the tree. 

But in the case of growing fungus for your trees, I think the higher the nutrients in the medium the better. I grow mushrooms to eat and can tell you that most species enjoy an 'enriched' substrate, however these enriched substrates are far more prone to contamination from other competing bacterial and fungi.


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## Old McDonald (Dec 27, 2013)

Mordalphus, Thanks for your further reply. I have logged in a few times, but have lost connection before I could post – a common occurrence in bad weather, so I am drafting this offline.

I think, but do not know for certain that you are right about moisture being the only difference. I also agree with you about the difference between fungus and underwater micro-organisms, but mycorrhiza do draw nutrients from leaf litter in a natural situation and I expect they would do the same from mulches of leaves – comfrey in my case. Summer mulching is my requirement, when the comfrey is growing, and it is used partially to lower soil temperature around the tree, and partially to benefit from the fertilising effects of the comfrey.

I also agree with your view that the more nutrients in the mulch the better for me. This was the reason that I thought the same might apply for growth of periphyton in your tanks, but if a lot of periphyton growth is not required, then that negates my thoughts. On my last farm I grew several mushroom species as part of the business and contamination was indeed an issue. 

I have decided to continue to mulch with fresh comfrey rather than dead or dried since, following your “more is better” view, the fresh will also provide a damp medium that should suit the mycorrhiza better than a hot dry one.

Again, thanks to you and everyone else who took the time to answer my curiosity.


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## ilurk (Jan 16, 2012)

McDonald, if your objective is to regulate soil temperatures, would it not be better to use dried leaves? I'd think green leaves would have higher bacteria content where dried leaves would favor mold. Green leaves would likely decay at a faster rate since bacteria would increase activity in higher temperatures and cause more compacting. Additionally, compacting decrease air pockets that insulate and moisture could become an excellent conductor of heat. Color of dry vs green leaves may also affect absorption of sun/radiation.
Regarding harvested dry leaves vs dropped dry leaves for shrimp nutrition, i think everyone has a different opinion. In my opinion they're the same. Just like some fishermen insist fishing is better on full and new moons.


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## Old McDonald (Dec 27, 2013)

ilurk, Soil under a comfrey mulch is much cooler than uncovered soil in summer here. It does not rain from about mid-May to early October - slightly variable of course, but I do irrigate. Almost any mulch is preferable to none, although having some experience of small heaps of lawn mowings in other countries, I think that might not be advisable.

Thanks for your remark re shrimp.


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