There is nothing like real wood aquarium driftwood to make any aquarium look more natural and beautiful. In most natural aquatic habitats, fallen trees, roots, logs, and other chunks of wood are all part of the natural environment. Fish and other aquatic life use these woody debris for places to hide and find food, and beneficial bacteria colonize on wood.
Aquarium driftwood is not necessarily the kind of wood you pick on the beach, driftwood is what any wood that is put into an aquarium is called. Some types of wood are better than others for driftwood because of their different qualities and chemical properties. A good wood for an aquarium is wood that looks good, provides habitat, resists decay, and is not chemically toxic.
A common problem with natural aquarium driftwood is wood will release tannins into the water. Although tannins at low levels are not directly toxic to most fish, enough of it can reduce the pH of the water and also color the water. There are some aquarium driftwoods, such as manzanita, that are popular because they release less tannins than others. Manzanita is also a wood that will sink in water after it becomes saturated. The ability to sink without being weighted is another good characteristic of good driftwood for aquariums.
It is highly recommended that you first soak a new piece of aquarium driftwood in water for a while before putting it in your aquarium. Soaking it will leach out much of the tannins and and saturate the wood so it will sink. The water should be changed every day or two and depending on the type and size of wood, it can take a couple weeks to a couple months for the higher levels of tannin to leach out. You should notice over time less color in the water as you continue to change the water.
Just picking up any piece of wood and putting it in your aquarium is not always a good idea. Depending on where you get the wood, it may be carrying chemicals that can be toxic to fish or you may introduce living organisms into your aquarium that can harm fish or plants. There are many ways to prepare wood for an aquarium and there is not always a right way. Different aquarium owners have different methods of treating driftwood which can also vary depending on the type of wood and where it was found.
Hardwood or Softwood for Aquariums
Many aquarium owners recommend that only hardwoods be used for driftwood. Hardwoods come from broadleaf trees and are generally better for an aquarium than softwoods. Softwoods come from cone bearing trees like pine, fir and cedar. Softwoods are resinous and the resins contains substances that are best left out of the aquarium. Many softwoods will also tend to decay more readily than hardwoods.
You can usually tell a wood is a softwood because it will have a pine or cedar-like scent. If you can dig a fingernail into the wood it is probably a softwood.
Sterilizing Aquarium Wood
If you find a piece of wood on dry ground or cut it from a tree and let it season it is most likely safe from disease or other harmful pathogens. But many aquarium owners like to treat it anyway just to be safe. That is a decision you will have to make. If you found the wood in a body of water, especially a stagnant pond, you will probably want to treat it. If you find the wood in a clear stream it is probably more safe.
Wood should first be scrubbed clean to remove dirt and debris. It is usually best to remove the bark since it may start to decay and fall apart once in your aquarium. Bark can also contain and release more tannin into the water than the wood will. Remove any moss or lichen since it may be toxic to fish.
One way to sterilize the wood is to heat treat it. You can boil the wood in water for a couple hours, some say up to 8 hours, while others may only boil it for 30 minutes or less. For larger pieces of wood, the extended boiling times are to make sure the wood is heated all the way through.
You can also heat treat the wood by placing it in the oven and baking it. You will just have to be careful to not allow it to get hot enough to catch fire. I would suggest not getting the wood much over 200 degrees Fahrenheit or much over boiling temperature, both for fire safety and to keep from harming the wood. If the wood is wet you may not want to use the oven since the wood may vent a lot of steam if you get it too hot. The heat will also dry the wood out, which may mean more work for you in re-saturating the wood so it will sink later.
Sometimes an easier way to sterilize aquarium driftwood is to soak it in a bleach solution. Make a solution of about one cup of bleach for 5 gallons of water and soak the wood for 3 or 4 days. Then soak the wood in fresh water for 4 or 5 days, changing the water every other day. Just make sure all the bleach is gone before placing the wood in your aquarium. At this point you may want to continue soaking to reduce the tannin in the wood.
Removing Tannins from Aquarium Driftwood
Most wood will usually release tannin into the water which can lower pH levels and discolor your water. Some aquarium owners like the brownish color that resembles a blackwater Amazon type environment. For some this goes along with their Amazon aquascape and can be good for many South American Fish. But most aquarium owners prefer clear water.
If you found your aquarium driftwood in the water, chances are it will already have most of its tannin leached out. If the wood is old and weathered it may also have less tannin. If it is fresh wood you will probably want to soak the wood for a while before you introduce it to the aquarium to let the tannin leach out. Depending on the size and species of wood, this can take from a couple weeks to a few months. The soaking water should be changed every couple days. Much of the tannins will leach out from soaking but it will not get it all out. Wood in an aquarium will probably always leach some tannin into the water but at low levels it is harmless. Some people like to boil the wood first to help remove tannin.
image source: driftwooduk.com | article source: aquariumdriftwood.org