Airborne Toxins Near the Aquarium: Aerosols, Fumes and Smoke

Sprays, fumes and smoke do not need to touch the water to poison it: they dissolve in at the surface. Open tanks and running air pumps are most exposed.

A contaminant does not have to be poured into a tank to poison it. Many of the worst aquarium accidents come from the air: aerosols, fumes and smoke that drift across the room, settle on the water surface and dissolve in. Because the danger is invisible and indirect, it is easy to overlook until fish are already in distress.

How airborne toxins get into the water

Many household chemicals are volatile organic compounds, organic chemicals with a high vapour pressure at room temperature that readily evaporate into the air. Common indoor sources include paints, varnishes and lacquers, paint strippers, cleaning and personal-care products, and the fumes from cooking and cleaning. Once airborne, these compounds can dissolve into and contaminate water, and some VOCs are dangerous to health. At the aquarium, the point of entry is the water surface, where the tank constantly exchanges gases with the air. The same VOCs that cause eye, nose and throat irritation and headaches in people in a poorly ventilated room are the ones accumulating over an exposed tank, so a smell strong enough to notice is a warning worth acting on.

Common airborne culprits

Aerosol sprays: air fresheners, deodorant, hairspray and furniture or cleaning sprays.
Insect sprays and foggers or 'bug bombs', which are extremely dangerous to fish.
Paint, varnish and solvent fumes, and off-gassing from new furniture.
Cigarette and cigar smoke, scented candles and incense.
Cooking fumes and airborne grease, especially near a kitchen.

Prevention

Never spray aerosols or insecticides in the same room as an aquarium.
Before any spraying, painting or fogging, turn off the air pump and any surface-breaking flow to slow uptake at the surface.
Cover the tank with its lid or a sheet during and after the activity, and ventilate the room well.
Keep tanks away from kitchens and from areas where people smoke.

If a tank is exposed

Treat it as any contamination emergency: stop the source, ventilate the room, and carry out large, repeated water changes with dechlorinated, temperature-matched water. Run fresh activated carbon to adsorb dissolved organics, and restore aeration only once the air is clear so you are not pulling more toxin in. Watch for gill irritation, gasping and distress, and move livestock to clean water if the exposure was heavy.