Natural Aquarium Substrate, Rocks and Wood
Using natural aquarium decorations is beneficial for fish and the entire fish tank mini ecosystem. Here’s a short list of natural aquarium decorations you can use:
Gravel Substrate
Substrate plays an important role in the tropical fish tank. Besides an ornamental value it holds plants in place and retains beneficial bacteria that help process fish waste products and clear the water.
Typical substrates include pea gravel, silica sand, silver sand , grit and colored gravel. Ant gravel in the aquarium should be neutral or inert, meaning it should not dissolve in the water or in any way change water’s chemical properties.
Pea Gravel
The best general purpose aquarium gravel fits in 2-5 mm range. Anything bigger and all the fish waste and uneaten food will pass through the gravel and rot in the gravel. This material is good for digging fish as the rounded edges will not harm the fish’ scales or mouth.
The spaces between gravel particles allow the plant roots to ‘breathe’ easily and the water to freely penetrate the space to wash out any toxins. The other positive is the ease of cleaning. It is not very compact so the base depth to support plants should be about 5 cm (2 in).
Gravel is widely used for aquascaping and it can be used to create perspective and depth by modeling the slope. Certain plants need deeper substrate for support or root networks and sloping allows creating deeper areas.
Many fish species create their own space in the gravel in the courtship period or use it as a nest for eggs and the fry.
In aquarist shops you can find coated gravel, this epoxy coat can be washed off in time by excessive agitation while cleaning the gravel. Never wash coated gravel in hot water.
Aquatic Sands
Silica sand is also widely used for creating natural looking aquaria. The earthy color resembles natural bottom colors from tropical regions.
Silver sand is a very popular substrate as it can be found in many natural locations. Both types of sand have very small grains.
Before using any of the sands it is necessary to remove any small particles by washing them thoroughly until the water runs clear.
Certain plants grow better in sand than in the gravel but there is not much water flow between the sands particles. Installing cable heating in the sand will prevent the stagnation.
Grit has larger grains than sand (about 2mm) and provides good support for the roots.
Special Substrates
Some manufacturers mix the substrate with live water purifying bacteria and water clarifying agents and conditioners. Using this type of gravel has many benefits for starting new aquarium.
There is also a range of substrates with concentrated fertilizers used for planted aquaria. Those fertilizers release the supplements slowly for the plant’s roots.
Other kinds of specific substrates are offered for keeping a specific specie of fish.
It’s important tyo remember that light colored aquarium substrate will cause the fish to lighten their colors, on the other hand some species will show off their colors best in the bright environment.
Fish Tank Rocks
Rocks in aquarium are useful for aquascaping to create a natural look and for creating hiding places for fish. Any rock used in a fish tank has to be inert (non-reactive) so it won’t change the water chemistry. It is vital to test the water on regular basis.
Types of Rocks for Aquarium
Lava rock – it is quite light as it contains air but it can be quite sharp and therefore not suitable for algae eaters. There is a type of lava rock that floats making it useless in aquaria, find out before purchase.
Slate – generally it is neutral and a great material to build hiding places, it is also easy to clean and to break into smaller pieces.
Cobble stones – made of granite and rounded shape, can be quite heavy, comes in many sizes and colors.
Sandstone and Limestone can also be used but the water needs to be tested for pH and hardness increase, however some species need high pH water. These stones will look best in aquascape as they resemble the natural boulders.
Rocks are heavy and need to be placed on the substrate or best way is to line the place for the stones with special foam or sponge. Heavy pressure from the stone can break the bottom glass and cause leaks.
Aquatic Wood
Not every wood is suitable for placing in the aquarium especially fresh wood. The most popular is driftwood which has been in the water long enough to be safe for the aquatic organisms. But still, as any other organic matter the wood will eventually decompose so monitoring the changes in the water chemistry is essential.
Driftwood or Bogwood can change the color of the aquarium water, to avoid this it is best to pre-soak the wood as long as possible before placing in the fish tank. Adding active carbon will also help to clarify the tan of the water.
Alternative to pre-soaking would be boiling the wood to remove the tannins.
Some algae eaters can digest tiny pieces of the driftwood scraped from it’s surface together with algae. It forms a part of their natural diet.
Many aquatic plants that should not have their roots placed in the substrate may be attached to the driftwood.
Hard Roots Wood
Another type of aquatic wood is the root wood, widely used to recreate natural look of tropical habitats. To achieve a nice effect some ferns and mosses are planted on wood and create pleasant composition. Initially those plants get attached to the wood with a fishing line and with time roots penetrate the wood and the line can be removed.
Other types of decorative wood include Curio wood, which is twisted and gnarled and Mopani wood which surface comes in two nice contrasting colors.
