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.
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.
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.
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.
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.
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.
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.
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.
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!
EDIT: Internet-sourced images added.
