As of January 7, the water authority in the Edinburgh area will be using chloramine instead of chlorine to disinfect tapwater.
Fishkeepers and retailers are being urged to ensure their water is properly dechloraminated.
More than 10% of the UK's tapwater supply now contains chloramines - a growing number of authorities are making the switch.
Compared to chlorine, chloramines are much more stable and can persist for several weeks. Chloramine can't be removed by boiling, leaving the water to stand, aerating it, or spraying it into the aquarium or pond through a hose.
Chloramine can be removed using a combination of activated carbon and zeolite. Some RO units will remove it if equipped with carbon filters. The easiest way to remove it is to use a chemical water conditioner.
Two popular products, Kent Ammonia Detox and API Ammo-Lock2 are capable of removing chloramine and the resulting ammonia. The vast majority of other dechlorinators do not do this.