So after 9 weeks of cycling my 20G tank with a 10G sump...i noticed that one of these guys just appeared out of nowhere...after a day, i saw another one in my sump then I did a partial WC to bring nitrates down to 15ppm(i have a dsb and some fernlike macroalgae and sargassum in my sump.
After 2 days...another one appeared in the main tank....and just as i arrived home today (after 2 days)...2 more appeared in the sump! there are a total of 5 Stylocheilus longicauda in my tank right now...the speed as to how they appeared worries me that they could turn out as pests...any thoughts?