It was officially confirmed 4 months ago that we had the dreaded Argulus Mongolianus fish lice in our water. We had been adding garlic powder to our supplement feed but things didn't improve, in fact it was getting worse over time. Very lethargic fish with dozens of lice in and around the gill area, loosing carp daily for weeks on end.
Our only chance left was to try the Natrapel, within 2 weeks of applying it to our feed we noticed a big improvement in the condition of the fish and less and less Argulus attached to the said fish.
Angling improved over time and we where finding less and less dead carp. This last week we had a match, all caught well and not a single Argulus found on any of the fish.
We can't guarantee it is the Natrapel that has deterred the lice as we've no scientific evidence to back this up but the club and myself feel that without it, we would certainly be in dire straights and facing ruin.