I bought first 2 and one of the was just gone a day after I have introduce them in my DT. First they has been in my refugium for 2 weeks- The one left just adapt well. After a month I bought another one - probably a male - male do have some filament at the tail.
The whole picture - here
After 2 weeks in the refugium - time for the DT. this is the first time in this aquariums history where I got a fight when I introduce this fish. The first introduced (a female) was rather angry for a week - but now it works well.
Fine - biting - I have not seen them hunting other fish but some of my thread fine cardinals have damaged fins. However - I had it before too - I do not think it is my Paraluteres prionurus
Sincerely Lasse