Adding Tree Leaves to a Tank for Biofilm, (UK Trees only).

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Bruce Leyland-Jones

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I went a-wandering today and the leaves are now starting to turn and fall.
I've been researching shrimp and biofilm and what not and decided to post what I've learned about some leaves...

NOTE that I'm only talking about the trees I'm familiar with, here in the UK. You'll have similar trees elsewhere, but I didn't want to start guessing their properties...and different names. You'll also have your own unique species to think about.
 
Shrimp need a varied diet, but especially like a more mature tank*, with an abundance of ‘biofilm’ present. This includes algae, waste organic materials and bacteria.

Many of us with a properly cycled tank will have a tank that contains a healthy population of bacteria, that same stuff we carefully cultivated back when we first cycled our tank and now rely on to help keep our toxic waste levels down to a manageable level.

Assuming that our tank is cycled, we shouldn’t need to add extra bacteria for our shrimp to munch on…or do we? If we like to add a healthy variety for our shrimp’s diet, then we can buy all manner of excellent foodstuffs, specifically catering for their tastes. Dennerle, for example, offers a good range of goodies, designed to keep our shrimp all perky and healthy.

But what about ensuring that the level of biofilm remains healthy for all tank inhabitants, without simply leaving food to rot? A common source for biofilm appears to be leaves, added to the tank, and allowed to decay within it.


Leaves can stain the water harmlessly, with their tannin content, change the pH without resorting to artificial chemical buffers and are a great supplementary food for shrimps and snails.

Adding leaves to the tank can also contribute to the authenticity of several biotopes you might want to replicate within your small, glass box.

So what leaves can we add, that are safe enough and won’t decay in such a way as to leave the water cloudy, as it may well be, back in the natural environment?

Beech
The Beech is another common tree, found in the countryside and parks. The leaves are quite small and thin and are, therefore, easy to accommodate in a tank. Whilst they do possess tannin, their content is not as high as that of the oak, for example and beech leaves will only stain the water a yellow tint, rather than a brown. They will only slightly reduce the pH.
Copper_Beech_Fagus_sylvatica_f._purpurea_Autumn_Leaves_Closeup_3008px.jpg

Hazel
Hazel is another common tree within our countryside, having been coppiced for millennia, more for the wood than the tasty nuts. It produces slightly larger leaves than the Silver Birch, but these also take a long time to decompose. Unlike Silver Birch, Hazel leaves will give the water a slightly brown tint and will reduce the pH of the water slightly. However, whilst the leaves will cultivate their own biofilm, sucker-mouth fish and shrimp will usually not eat them.
hazel.jpg

Hornbeam
This is a lesser-known tree, in spite of it being extremely common in parks, (it is very tolerant of pollutants). As with the Beech, it has small leaves and is a very good substitute for the Indian Almond/Catappa leaf. As such, they can lower the pH of the tank very quickly, so care must be taken with their usage. These leaves contain a lot of tannin and, as a consequence, can stain your water significantly.
hornbeam.jpg

Mulberry
Thought to be one of the best shrimp foods, Mulberry leaves are also enjoyed by many sucker-mouth fish. The green leaves have a high nutritional value, being high in protein and, as a bonus, they will not change the water parameters. Mulberry trees and bushes are not all that common in the UK countryside. However, they are well worth seeking out. That said, they are a popular garden tree, often producing excellent fruits for us to eat and can also be found within the gardens of stately homes.
mulberry.jpg

Oak
We have many oak species in the UK, most widely available in the countryside, as well as in parks and gardens. Whilst they may differ in the shape and size of their leaves, they all contain a relatively high level of tannin. This makes them a useful pH reducer and, of course, they will stain the water a shade of brown, not too dissimilar from tea.
Oak-leaf.jpg

Plane Tree
Another tree commonly dominating urban and suburban parks, thanks to its tolerance of airborne pollutants. The large leaves of the Plane tree have very little effect on water quality and take a long while to decompose, making them useful additions for those of us wanting leaf litter at the bottom of our tanks. Whilst the leaves themselves may not be greedily gobbled up, the biofilm they’ll produce will be.
plane-leaves-3.jpg

Silver Birch
This is an easily recognisable and very common tree, found right across the countryside and both suburban and urban green spaces. It has small leaves and a characteristic silvery white bark. The leaves will not colour the water, nor will they alter the pH. Taking a very long time to decompose, these leaves are great for providing sanctuary for substrate dwelling shrimp and other invertebrates.
silver birch.jpg

Sycamore/Maple
The sycamore is another very commonly available tree, with large and recognisable leaves and, of course, the ‘Spinning Jenny’ seed pods. The leaves, in an aquarium, will have quite a marked colouring effect, quickly tinting the water like a well-brewed tea. Having lost their tannins, the leaves will rapidly decay and become semi-transparent, at which point they make very desirable shrimp and snail food. The leaves will also drop the pH for a short while, but this will rise again soon, on its own accord.
sycamore-leaves.jpg

Walnut
These leaves are known for their very positive effect on the health of fish and shrimp. For example, they are known to be able to cure bacterial and fungal infections and to reduce stress. NOTE that these leaves will not lower the pH, nor colour the water, to the same extent as the commercially available and promoted Indian Almond/Cattapa leaves. Again, walnut trees are not as common in the countryside as thy once were and, as with the Mulberry, are more likely to be found in parks and gardens. Some may even produce fruit!
walnut.jpg


EDIT: Internet-sourced images added.
 
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Lol I went for a walk with daughter earlier and was looking at the oaks leaves and thinking about using them.

Great post, really useful information.
 
Have you read this yet?
I missed that one, but very useful.
Great minds think alike, and all of that.*
Of course, I'd expect other leaf-related contributions by those with more knowledge than myself, to participate in the thread.


*Or is it 'fools seldom differ'? :p
 
I've never used local leaves. I'm scared of using the wrong kind of leaves, or leaves contaminated with a chemical/bird droppings etc :blush:
 
I've never used local leaves. I'm scared of using the wrong kind of leaves, or leaves contaminated with a chemical/bird droppings etc :blush:
That article you sent the link to supplies the sort of safety info I was in the process of typing up...I don't have to now that someone else has done such an excellent job of it.
Autumn has only just started in earnest, so there aren't too many genuinely 'fallen' leaves about, just yet, but whilst some do show signs of insect or fungal trouble, there are plenty of clean and whole ones about.
 
This is a great post Bruce, thank you for writing it. I have often wondered about whether you can add our native species to our tanks. You often see specific leaves for sale on various sites. It’s given me a few ideas.
Have you added any yet?
 
This is a great post Bruce, thank you for writing it. I have often wondered about whether you can add our native species to our tanks. You often see specific leaves for sale on various sites. It’s given me a few ideas.
Have you added any yet?
I'd already done some serious reading, but it was my autumnal walk today that got me going. I've got some aquarium gardening to do, before I start potentially complicating things with leaves. Whilst researching shrimp, I came across many, many references to the Indian Almond leaves and, when I saw the price, I wondered...
 

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