Must agree about velvet loving coccinas - I've got your trio of gouramis in with an infected brownorum and it doesn't show up on them at all!
Good luck with the treatment, seems a shame for something to go wrong now you've gotten them looking like actual fish :lol:
Very interesting siphon, but the waste in that video is dramatically intensified - I don't think a single male could produce that much even in a week! XD