Most aquarium sculpture is made from nontoxic plastic that has been molded into interesting shapes of natural or whimsical design. Though some aquarium sculpture may look nice on the webpage or sitting on the shelf, each piece should be considered in context of the environment of your specific tank and the needs of its residents. Carefully selected aquarium sculpture is not only a decoration, but functional, like furniture in a home.
If some fishes in your tank require a good amount of free swimming space, such as bala sharks, opt for aquarium sculpture that does not extend into the mid and upper levels of the tank where the balas swim. The exception is if your tank is so large that the aquarium sculpture occupies insignificant space, as in the case of a 150-gallon (568-liter) tank.
When considering swimming space, bear in mind that most people underestimate the needs of larger fish. A 60-gallon (227-liter) tank is not a large tank for occupants larger than four inches (10 centimeters). It is a myth that a small tank will keep fish small. It will only cause them to grow more slowly and to endure more stress, making them more susceptible to disease.
Some aquarium sculpture is made with a large hole in the center so that fishes can pass through without having to maneuver inside the decoration. If the decoration must extend into the swimming space, this can be a compromise for top-swimming fish. Another choice is a whimsical decoration, such as a treasure tank with cascading bubbles - an apt decoration for “circling sharks” above!
Tiny fish like neon tetras enjoy swimming in and out of aquarium sculpture, so choosing something hollow with passages throughout will make the fish feel safe. This is even more critical if there are larger tankmates present. In this, case you might provide a sculpture in the form of a castle or lava formation with passages too small for the larger fish, so that the neons can enter the aquarium sculpture for refuge. In the wild, plants provide natural refuge for small fish and reduce stress. Aquarium sculpture surrounded by live plants adds authenticity to the decoration and makes for happy fishes.
Catfish love exploring the bottom of the tank, so aquarium sculpture such as hollowed logs are especially nice for this type of fish. Note that the holes in the decoration should have plenty of room for the fish to pass through when fully grown. Growing fish often get stuck in holes they could once pass through. A typical pattern is that a lodged fish will struggle until it injures its gills and exhausts itself, then dies – all while the aquarium owner is sleeping or at work. This is easy enough to avoid by choosing the right aquarium sculpture for your little wet pals.
Often, aquarium sculpture is placed next to terrarium sculptures in pet centers. Though they may look similar, do not place anything in an aquarium that was not made as an aquarium decoration. Plastics and paints can leach harmful chemicals into the water that will kill your fish, so purchase only genuine aquarium sculpture.
Note that ceramic or plaster aquarium sculpture can leach calcium, which raises pH values and adds hardness to the water. This may not be a concern for hard water fishes such as cichlids, but it is not desirable for soft water fishes such as neon tetras, angelfish, and gouramis. Plastic aquarium sculpture is desirable because it does not change water values.
By considering the size of your tank, its aesthetic environment, and the needs of the fish, you should be able to come up with excellent choices for aquarium sculpture. The right decorations will improve the beauty of your tank while providing safety, entertainment, and in some cases, added oxygen to the fish. Remember to rinse new decorations off before introducing them into the aquarium. If they are hollow, spill out all trapped tap water before placing them in the tank. Also, vacuum under and around aquarium sculptures when cleaning.