In most cases, the general aquarium contains fish originating from the natural environment, where rocks and stones are abundant. If you keep fish from stony reservoirs, an absolute requirement is the presence of stone structures in the aquarium.
Stones, as well as the substrate, should not affect the chemical composition of the water – except when this is the intention of the aquarist. They must not contain minerals that may be poisonous. It is also important to avoid stones with sharp chips or protrusions that could be injured by the fish.
This is especially dangerous if there are restless fish in the tank that start to panic all over the tank in fright. If stones are to be used as a substrate for spawning, they should at least in some places have a smooth surface.
If there are fish in the aquarium, usually laying eggs in crevices, you need to create their imitation.
Buying Aquarium Stones
Some stores have a small selection of stones – usually lime tuff and slate, and sometimes unsuitable types of slate are offered. It must be borne in mind that not all stones sold in pet stores are suitable for aquariums.
It is desirable that the aquarist had an idea about natural rocks and knew their names. This will give him the opportunity to independently collect stones if he wishes. Images of rocks and their composition are usually given in illustrated books on geology; therefore, it is easy to master the necessary information about stones.
However, in order to avoid undesirable situations in your tank, when searching for stones, rocks containing calcium and manganese salts should be avoided. A fine decoration of the aquarium can serve stones from the beach, polished with water.
Stones used in aquariums
Gneiss. This is a very hard metamorphic rock.
It is often striped, usually gray, gray-green or white, sometimes pink. Usually fine-grained.
Almost neutral. Good stones for aquarium, suitable for any purpose.
Granite. Solid rock of volcanic origin, has specks, gray, black or white, mainly used for decorative buildings.
There is also a special kind of orange color. Almost neutral and is an excellent versatile material for the aquarium.
Limestone. Sedimentary rock consisting mainly of calcium carbonate. Some limestones also contain magnesium salts.
Limestone can range from fine-grained and hard to coarse-grained and crumbly. Usually grayish or whitish.
May include fossils. Increases or buffers stiffness and pH.
Sandstone is gray. A very hard metamorphic rock, grayish, speckled.
Almost neutral. Suitable for use in general aquarium.
Sandstone. Sedimentary rock consisting of sand. Its composition and, consequently, the effect on the chemical composition of water are determined by the composition of the sand.
Some sandstones increase water hardness and pH. There are soft and fragile sandstones, they are not suitable for use in an aquarium. Slate
A very hard metamorphic rock, known for its gray color (usually dark gray) and layered structure. It can easily be split into relatively thin sheets or plates with flat edges.
Some shale contain between layers of intrusions of other minerals, manifested in the form of painted veins or layers on the side faces of the shale. Such slates are unsuitable for use in an aquarium.
However, pure slate, including old slate slabs, is an excellent neutral rock. (Chips of shale are sharp enough for unwary fish to be seriously injured. This should be taken into account when building rocky structures.)
Lime tuff. Very rough and brittle limestone.
It is popular with aquarists who keep fish originating from alkaline waters and underwater rocks. It is porous and light, and large structures can be built from it, supported on the rear glass of the aquarium and without overloading.
As a spawning substrate, it is absolutely useless, because its surface is too rough.
Tips on choosing stones:
Do not collect stones in the area where there are mines or quarries and mining of metal or mineral ores occurs. If there are quarries somewhere nearby where stones are used in construction or for the manufacture of tombstones and statues, this is a good sign, since such stones must have a uniform structure and do not contain inclusions of foreign minerals that may be toxic. However, this does not exclude their effect on water hardness and pH.
Valuable information about rocks can sometimes be provided by workers in quarries.
Avoid areas where stones may be contaminated, such as pesticides or radioactivity.
Do not take stones with metallic streaks or layers of rust color, as well as stones containing colored crystals. However, if you see white or transparent crystals or streaks, it is most likely quartz, it is safe.
Do not use soft or crumbling stones (with the exception of lime tuff – in alkaline aquariums).
Do not forget that matte grayish-white stones are most likely limestone, and stones, in color and structure resembling sand, are likely sandstone.
Look for stones with a uniform color, evenly spaced specks and a uniform structure.
Among the stones polished with water, choose those with a uniform surface and no holes or cracks.
Remember that stones containing fossils are usually limestone.
Avoid brightly colored stones (if you are not sure that they are safe), because this color may be characteristic of some unwanted minerals.
Do not take stones from the walls and do not spoil the environment in any one place. If possible, ask permission to collect stones and try not to leave any signs of their activities.
If possible, leave the rural landscape untouched. In general, it can be said that the simpler the stones look and the less interesting they look, the more likely they are safe in terms of toxicity, although they can still affect the chemical composition of the water.
This can be verified using the “acid dough”, which was discussed above in the section on materials for soil.
And one last note: do not abandon the decoration of the aquarium with stones just because their acquisition requires some effort. As soon as you have suitable and safe stones, they will never collapse or wear out completely and become a long-term valuable acquisition for your hobby.
If you do not feel sufficient confidence in your abilities and knowledge to independently collect and test natural stones, it is better to contact pet stores. Some stores sell artificial stones, including the so-called lava, which is not a real volcanic lava at all.
Some artificial stones are surprisingly similar to real ones, although the range of their sizes and shapes is rather limited and they are quite expensive. But they, like the real ones, will serve you all your life.
Preparing stones for use
All stones should be thoroughly rinsed in water (without soap and detergent) to remove dirt, moss and lichen from them. Particular attention should be paid to cracks and holes where dirt, insects, etc. can be found. It is better to submerge stones collected in natural waters in boiling water in order to destroy all aquatic creatures that could settle on them. Among these creatures may be pests, as well as pathogens and parasites.
Instead of boiling, stones can be dried for one to two weeks.
Shells can not be considered a suitable decoration of the general aquarium, because they consist of calcium carbonate and can affect water hardness and pH. However, some species of fish (mainly shell-dwelling cichlids from Lake Tanganyika) certainly need spiral shells, which they use as shelters and spawning grounds. To do this, usually take the shells of French edible Escargots snails, which can be purchased at gourmet stores or ordered in French restaurants.
They are ideal for most fish species. Shells, sold as interior decoration, are also suitable, provided that they are not painted or varnished.
Shells from the sea coast must first be sterilized by boiling, and then completely clean all available surfaces. Those shells that have been empty for some time are well polished with water and more preferable than those that may still contain the remains of dead mollusks.
Obviously, whatever shells you choose, they must first be of suitable size to accommodate the fish that need them.
Snags can be a wonderful decoration of an aquarium. In addition, wood is a natural type of shelter in the natural habitats of fish.
However, this does not mean that any piece of wood found in the wild is suitable for an aquarium, even if you find it in a river or stream. The aquarium does not have such an advantage as the constant renewal of water, dissolving and washing out all toxic organic substances emitted by decaying wood.
In the aquarium, such substances can quickly accumulate and reach critical concentrations. In addition, natural acids are present in the wood, which can cause a noticeable decrease in pH. Usually, only certain, fairly safe types of wood are used – stained oak, cork, bamboo and coconut shells.
Since these types of wood can also release tannins and other substances into aquarium water, they require careful selection and preparation before use (see below). Usually they are placed in an aquarium only if their oxidizing effect is not capable of causing harm to the fish or if they are coated with varnish to prevent the leakage of harmful substances.
If you place unvarnished wood in an aquarium, it may also cause the water to resemble tea in color. However, it is quite natural for fish living in nature in streams flowing through tropical rain forests. However, some aquarists strongly dislike it.
You can get rid of the tea color by running water through a carbon filter.
Purchase of wooden items for the aquarium
Bog oak, as its name suggests, it is located in swamps and swamps. It represents the remains of ancient trees that have been preserved for centuries due to the effects of natural preservative agents such as tannins. Suitable sources of bog oak are usually strictly guarded by companies with “right to quarry”, therefore bog oak is usually purchased in stores, and not harvested in nature.
It is expensive, but it serves for many years and is a very attractive natural element of decorative design.
Corkwood – this is the bark of cork oak Quercus suber. It can be bought in some pet stores, as well as in flower and gardening stores.
Her own collection, as a rule, difficult.
Bamboo can be purchased at flower and gardening stores. Ensure that it has not been treated with preservatives or other chemicals.
In gardening, bamboo sticks are commonly used as supports for peas or beans and other garden plants. Use only new sticks, because old ones may be contaminated with pesticides or fertilizers.
Snag, that is, the flooded fragments of trees, can be collected on the beach or freshwater reservoir. It is necessary to collect only completely bleached (due to the effects of natural elements) and hard pieces of wood. Immersion in seawater usually results in the removal of most tannins from the wood.
However, the snag may contain salt residues that are undesirable in a freshwater aquarium.
Artificial snags for aquariums also sold in pet stores. Some of them are strikingly realistic and literally indistinguishable from real wood.
They are expensive, but, like stones, will serve you all your life.
Preparation of a tree for use in an aquarium
All wooden objects should be soaked (soaking should last for several weeks or months, not days) in order to remove all contamination. This process can be accelerated by boiling or soaking in hot water, which needs to be changed many times.
Soft wood should be cleaned and scraped as long as possible.
The coconut shell in winter can be hung in the garden as a bird feeder and left there for the whole summer, then by the autumn it will be perfectly cleaned due to the effects of weather.
The problem of harmful substances can be quickly solved with the help of wood varnish. In this case, the varnish must be waterproof and non-toxic.
However, the tree in most cases has cracks and cracks that cannot be effectively sealed, so the slower way is still more reliable. In addition, some fish (for example, catfish and cichlids from the Uaru genus) are accustomed to scrape and gnaw wood and may be poisoned with varnish. This can happen even if the lacquer is nominally safe, because the concept of lacquer safety does not provide for cases of its use in food, etc.
Objects such as clay ceramic pots for plants or saucers, as well as pipes are often used as a cave for aquariums. Fishes willingly occupy such “caves”, preferring them to more natural structures built of stones. If such objects are too unsightly, they can be hidden between stones or among plants.
You can put the flower pot on its side or first break off a piece of the rim (this will be the entrance), and then turn it upside down and put it in an aquarium. Drainage trays or saucers are also usually used upside down, having previously made an inlet in the rim.
Ceramic products must be new, otherwise particles of pesticides or fertilizers may remain in the water, remaining in the porous clay even after thorough washing.
Plastic pots should not be used, as the plastic from which they are made may be toxic. Plastic pipes used to supply drinking water are suitable for use in an aquarium, however pipes for sewage should not be used.