My aquarium and filter are heavily colonized by what I'm pretty certain are leeches. They are flattish worms that "inch" along, grabbing with their head and tail ends. I used to see them attached to fish (who subsequently died), but more recently, they seem to be free-living. There are...
today I started treating my fish for gill flukes with praziquantel tablets. I'm following this treatment schedule reccomended by Lupin :
25/7 -- remove carbon, perform water change with vacuuming, and add Prazi to tank
26/7 -- add Prazi
27/7 -- do nothing
28/7 -- do nothing
29/7 -- do nothing...