sera guide - Healthy pond fish

43 8 Preventing and remedying maintenance mistakes and intoxications tion of hydrogen sulfide which stinks like rotten eggs, and nitrite – both of them are highly ichthyotoxic substances. Therefore, be sure to check the function of your filter regu- larly and loosen the bottom ground while siphoning off the sludge. Heavy metals may also lead to severe chronic or acute intoxications. They are introduced by, for example, old copper pipes, lead con- taining wire on aquatic plants or unsuitable decoration elements. Lead and mercury are particularly toxic. Invertebrates and amphibi- ans react very sensitive to copper. Zinc and even iron (in concentrations above 0.5 mg/l) are also harmful. If in doubt, check the water values, e.g. by means of the sera Cu-Test. sera KOI PROTECT and sera pond toxivec bind and neutralize heavy metals. Further- more, they remove corrosive chlorine. In case of acute intoxications – also with toxic substances not mentioned here – it is always advisable to carry out a large water change and to remove the remaining toxic substances with sera pond super carbon.