Using the Same Net for Several Tanks: The Mistake That Spreads Disease
Using the same net, bucket or siphon across different tanks without disinfecting it in between is one of the most underrated routes of contamination in fishkeeping: a few drops of water are enough to carry parasites like ich or pathogenic bacteria into an otherwise healthy tank. A review by Whittington and Chong on the global ornamental fish trade (research on Google Scholar) points to shared equipment and poor biosecurity practices as among the main routes of disease spread in the ornamental fish trade. Find our other pointers in the care and grooming section and on the fishkeeping hub.
How can a simple net spread disease?
Parasites such as Ichthyophthirius multifiliis (white spot) and certain bacteria survive several minutes, sometimes hours, out of water on a damp surface. A still-wet net dipped straight into a second tank can deposit the pathogen there, even if no sick fish ever swam in that tank.
What equipment is affected besides the net?
The same principle applies to water-change buckets, siphon hoses, glass-cleaning sponges, and even bare hands if they aren't rinsed between tanks. On a quarantine tank, see our guide hospital and quarantine tank, the risk is at its highest, precisely because pathogens are most concentrated there.
How can you cut the risk simply?
The most reliable fix is dedicating a full set of equipment (net, bucket, sponge) to each tank, especially if a quarantine tank is part of the setup. When that isn't possible, a hot-water rinse followed by 24 to 48 hours of complete air-drying eliminates the vast majority of common pathogens without resorting to harsh chemicals that could damage the equipment.
Do you need to disinfect equipment between uses in the same tank?
No, that's only relevant between different tanks: within a single aquarium, all the residents already share the same water, so cross-contamination via equipment adds no extra risk. The good handling practice described in our guide net and stress-free fish handling still applies for the fish's welfare, though.
- A dedicated equipment set per tank remains the most effective measure, especially with a quarantine tank in the mix
- Rinse with hot water and air-dry for 24 to 48 hours any equipment that moves between tanks
- Never dip a still-damp net from one tank straight into another without that step
- Treat your hands like equipment: rinse them between different tanks
Frequently asked questions
Is air-drying alone enough to disinfect equipment?
For most common parasites and bacteria, yes, provided it's a full 24 to 48 hours of open-air drying.
Can you use bleach to disinfect a net?
Yes, at a very low dilution followed by thorough rinsing, but complete drying stays simpler and avoids any risk of toxic residue.
Does the risk also apply between two garden ponds?
Yes, the same principle applies: dedicated equipment or full disinfection between two separate ponds.
This guide is part of Planète Pets’s Fishkeeping universe. Our advice is general in nature: for any health concern, your veterinarian remains the only reference.