Rocks, bits of wood, gravel and other aquarium scraps could be harboring all sorts of pathogens and parasites just waiting to infect your fish. Disinfection is crucial, but the trick is to do it without poisoning your pets in the process.
Driftwood and river rocks might be nice decorations, but they aren’t safe until they’ve been sterilized. Brand new items from an aquarium store are usually OK -- though not always -- but second-hand and found treasures definitely need disinfection. The problem is that most disinfectants tend to be even more dangerous to fish than the organisms you’ve killed. Spraying the item with an antibacterial cleaning spray might kill the bacteria, and it will probably kill your fish, too.
Baking kills microorganisms without the use of toxic chemicals. It has a few drawbacks, though, notably that some items, including rocks, may crack, and you have to keep an eye on anything organic, such as driftwood, to ensure it doesn’t catch fire. If you decide to bake aquarium accessories, place them on a clean baking tray and bake for 20 to 30 minutes at 200 degrees Fahrenheit. Obviously, let the items cool before handling or placing in the tank.
Boiling tends to be the best option for small aquarium items, having all the advantages of baking without the disadvantages. Boiling also removes chlorine (although not chloramine on this timescale) from the water, which means you can use water straight from the tap. Place the items in a large, preferably glass pan, cover with water and bring to the boil. Simmer for at least 20 minutes.
Household bleach kills bacteria, fungi and invertebrates efficiently, although it can kill fish just as rapidly if you're not careful. A bleach bath, however, might be the only option for larger items, the tank itself, plants and any plastic liable to melt at high temperatures. Use approximately one cup of bleach per gallon of water, then soak or wipe the accessories or tank. A slightly more dilute solution is recommended for plants, about 1 part bleach to 20 parts water.
The key is rinsing, lots and lots of rinsing, using dechlorinated water for the final rinse. Afterward, air the items for several days, to allow remaining traces of bleach to dissipate. If you're using bleach to disinfect something absorbent, such as a large piece of driftwood, you’ll need to soak the item in successive baths of plain water over a period of several days.
Judith Willson has been writing since 2009, specializing in environmental and scientific topics. She has written content for school websites and worked for a Glasgow newspaper. Willson has a Master of Arts in English from the University of Aberdeen, Scotland.