Imagine having to spend an extended period in a room with no furniture of any kind. How long would it take for you to become bored and uncomfortable, even neurotic? Life in such barren surroundings is clearly not an ideal situation for humans — and the same is true for our fish. Though we may need to use bare tanks for specific reasons (such as spawning or quarantining) on a short-term basis, time and experience demonstrate that fish not only exhibit fewer signs of stress, but also become more outgoing and demonstrative of natural behaviors if they can retreat to protected areas when they feel like it.
These protected areas can also double as decor. The thoughtful placement of a moss-covered rock, an interestingly shaped hunk of driftwood strewn with Java fern or even a ceramic cast of a sunken ship can contribute a lot to the look of an aquarium as well as cater to the needs of your fish. There is a wide variety of hideaways and refuges available for aquaria. Let us consider the applications, benefits and caveats of some of the most popular hideaways.
Moss or Bushy Plants
One or more bunches of hardy, fine-leaved plants in your aquarium can provide refuge for many fish, from newly born fry to a subordinate adult. Some of the best for this purpose include Java moss (Taxiphyllum barbieri) or other mosses, Anacharis (also called Elodea), Hornwort (Ceratophyllum demersum), Java fern (Microsorum pteropus; especially ‘Windelov’ or ‘needleleaf’), Guppy grass (Najas sp.) and water sprite (Ceratopteris spp.). Most of these are hardy plants that do well in low to moderate light and do not require supplemental carbon dioxide. Their dense growth provides plenty of hiding places for baby livebearers, shrimp or just about any fish.
As a bonus, their extensive surface area encourages the growth of tiny organisms that provide readily available snacks for your tiny aquarium inhabitants. If you have herbivorous fish, the old standbys Java fern and Java moss are probably your best bet, as these are often ignored by otherwise plant-eating fish. If your fish are particularly determined herbivores or your nonherbivorous fish seem to attack your plants, anyway, consider trying a thicket or two of fine-leaved plastic plants instead.
Most soft, fine-leaved plants also make a good spawning medium for fish that scatter their eggs. I have spawned egg-scatterers, such as white cloud mountain minnows and danios, in thick patches of Java moss. Danios, at least, have reputations for feeding voraciously on their own eggs, but in my experience, by the time I remove the parents, enough eggs have found their way into safe crevices to provide plenty of fry.
If you do include live plants in your tank, you will need sufficient light in the aquarium. Most aquarium setups come with hoods that are not specifically intended for planted tanks. They provide just enough light to see your fish without encouraging too much algae growth. Under these conditions, Java moss will probably do fine, since it will often thrive in no more than ambient light. Java fern is also fairly tolerant of low light, but most of the other plants listed do better with 2 or more watts of light per gallon. That said, they may do fine with less if the tank is shallow and/or the plants are allowed to float on the surface where the light is more intense.
Terra Cotta Flowerpots and PVC Piping
Though they may be less aesthetically pleasing than driftwood or natural rock caves, terra cotta flowerpots and sections of PVC pipe are a mainstay in aquaria for reasons of utility. Some species of cichlids, such as convicts and kribs, use these caves as spawning sites. Others, such as the African Rift Lake cichlids, do best with plenty of retreats to help curb aggression, whether spawning or not. Many catfish, such as the bristlenose plecos, also prefer a long, low cavelike structure for egglaying. If your tank is used purely for breeding, there is no need to adorn these structures, as the fish are quite satisfied for them to remain bare.
On the other hand, if you wish to improve the appearance of the caves in your tank, you can use aquarium silicone sealant to attach aquarium-safe rocks or gravel to these caves. A little imagination, some silicone sealant and some lava rock can go a long way. For a greener look, Java moss, Java fern and/or Anubias plants can be attached to the rocks or gravel with rubber bands, black cotton thread or fishing line. Once the plants gain a foothold, the rubber bands or fishing line can be removed. Cotton thread will gradually disintegrate on its own. You will eventually have a pleasing patch of greenery camouflaging the true nature of the cave with a tangle of fronds, leaves, roots and rhizomes.
Aquarium Ornaments (Sunken Ships, etc.)
Though some of us have tastes that tend more toward natural aquascapes, plenty of aquarists enjoy the effect of sunken ships, Roman columns or lurking crocodiles of resin or ceramic. As long as they are sold for aquarium use, these structures are safe, in that they will not leach harmful chemicals into your aquarium water, and many provide crevices for your fish to take refuge.
Two caveats are worth mentioning, however. Some of these ornaments have sharp edges, which might lead to injury of some fish. These edges are of particular concern to certain goldfish with exaggerated eyes, such as moors or bubble-eyes, as well as to nervous or extremely active fish that habitually dash in a haphazard manner around the aquarium. It may also be possible for some fish to lodge themselves in tight crevices of some of these structures.
Driftwood (also known as bogwood) is widely available at aquarium stores. There are several varieties. Malaysian driftwood is interestingly shaped, dark and dense enough to sink even when dry. Unless pre-soaked, though, this driftwood will release amber-colored tannic acids into aquarium water. These will eventually peter out and disappear with regular water changes, but if you prefer, repeatedly soak and drain the wood for a couple of weeks before introduction to your aquarium to minimize the effect. Other types of wood available are Mopani wood and sand-blasted grapevine. Some types require prolonged soaking before they will sink. Some of these otherwise-floating woods are available cemented to a stone or piece of slate so that they will sink immediately.
One or more pieces of driftwood in your aquarium will provide small crevices and caves for a variety of species, such as shrimp, kuhli loaches and many species of catfish. They also serve as anchors for hardy plants, such as Java fern, Java moss and Anubias. Another reason to keep driftwood is that many suckermouth catfish, such as bristlenose plecos, appear to require small amounts of wood in their diets to remain in peak health.
It is possible to collect your own driftwood for your aquarium, but there are several potential problems. In some areas, collection may be restricted by law. “Wild” driftwood may bring pathogens, parasites or predators into your aquarium. Additionally, driftwood that you find yourself may introduce natural toxins or manmade pollutants into your aquarium. Those who do collect their own driftwood often boil it first to minimize these risks.
Rocks: A Weighty Matter
Usually, rocks purchased at an aquarium store are safe, but they should still be rinsed well before use to dislodge fine particles and/or dirt. Rocks you collect yourself may be perfectly suitable; on the other hand, they may contain calcium, heavy metals or other minerals that can wreak havoc with your water quality — and in severe cases, poison your fish. In some areas, rock collecting may be regulated or prohibited by law, so make sure to do research before you collect your own. When in doubt, purchase your rock from a reputable aquarium store.
Even moderately sized rocks are quite heavy, so be careful when situating them in your aquarium. Glass aquariums are quite strong and capable of supporting the weight of most aquarium rockwork if it is carefully placed and supported; it is wise to make sure that the weight of each rock is evenly supported. You can do this by situating the rock on a cushion of substrate, such as gravel or sand, which helps distribute the weight of a rock over a wider area. This can, however, create a “dead spot” in the substrate that is unreachable by a gravel vacuum unless the rockwork is moved.
An alternative that I have used requires some advanced preparation. First, determine which parts of the rock will rest on the bottom of your aquarium. You can do this by setting the rock on a piece of paper placed on a level surface. The contact points of the rock will leave visible indentations in the paper. You can then note where these points are and apply a generous dollop of silicone sealant to each of the points on the rock. Once the sealant has cured, the rock may be placed in your aquarium, and the blobs of sealant will function as cushions.
If you stack your rocks, do so carefully. Precariously balanced rocks may look attractive, but they may unexpectedly topple, due to human-caused vibrations, a sudden movement by large fish or even by seemingly innocent digging in the substrate. It goes without saying that this can have disastrous results for your fish, your aquarium, your floor and your relationship with any other individuals financially responsible for that floor. With a little planning — preferably prior to introducing the rocks into your tank — fairly stable rock formations can be produced. For even more possibilities, extremely strong epoxies and aquarium glues are available, some of which can even be applied underwater.
What About Seashells
Seashells have an undeniable appeal for many people, but they are not good additions to most freshwater aquaria. Even if you are sure they are clean and free from particles of the original inhabitants, they tend to leach minerals into the water, making it quite hard — to the point of being unsuitable for many fish. One notable exception to this rule is a dedicated “shellie” (Tanganyikan shell-dwelling cichlid) tank. These diminuitive cichlids’ lives center around snail shells, which not only provide a refuge and spawning site for the fish, but also help recreate the hard and alkaline conditions of their native Lake Tanganyika.
In nature, many fish use visual boundaries, such as rocks, plants or driftwood as territorial boundaries. The dominant of two cichlids, for example, will often decide that the entire tank is his/her territory when in a bare tank. That fish will then defend it to the detriment (and often death) of the subordinate individual. That same dominant fish in a tank with plenty of rocks, plants and/or artificial caves is much more likely to decide to set up shop in one area. It will defend that area fiercely but will not as doggedly pursue the subordinate fish past the boundary defined by, say, a particular rock.
It is a good idea to include plenty of extra hideaways in a tank of territorial fish. If there are more fish than retreats, the more subordinate fish in tank are likely to end up with nowhere to go. In some cases, such fish may even be killed by more dominant individuals.
Home Sweet Home
Providing your fish with the appropriate hideaways is a win-win situation. Your fish get a more comfortable home. You are rewarded with a more attractive aquarium with fish that exhibit a more natural range of behaviors, providing you with hours of fascinating fishwatching — and that’s what it’s all about, isn’t it?
“Driftwood/Bogwood” (forum posting). www.thekrib.com/TankHardware/ driftwood.html. Accessed December 3, 2007.
Pederson, M. “Desktop Cichlids: The Shelldweller Recipe.” cichlidrecipe.com/ shellweb. Accessed December 3, 2007.