I used Flubenazole for many years mainly in Rainbowfish fry tanks. Some fry
were only days old. I never had any problems at all with any fish and I
have raised hundreds of fry over the period.
It is also the primary product used in Europe for hydra and planaria and
I've never heard of any problems at all. It is very toxic to snail and
related animals. It is also the main ingredient in some commercial aquarium
I found this chemical to be very safe.
There is a similar product called Fenbenazole which can be a problem if
overdosed. It also can be used for treatment for hydra and planaria. Its
also used as a human? and animal worm treatment.