i love firefish! what a great reef fish.
i'm having trouble reading your post, Agu. i'm not sure whether you've got 2 or 3 firefish in there at this time. i'm presuming 2, correct me if i'm wrong.
also, from using the common names, i'm guessing you mean the red firefish aka Nemateleotris magnifica.
what are the other species of fish that are in the tank? it sounds like they are the only 2. if so, this is rather strange. characteristically speaking, N. magnifica is ALWAYS in plain view once eastablished in a tank. usually, they like a bit of a current. it will look as if they are getting tossed around sometimes, but they seem to like it and go right back into it. however, if something is bothering them, like a larger more dominant fish, they become VERY reclusive. you'll think they are dead. MOF, it is advised to wait atleast 2 weeks prior to purchasing a firefish once one disappears, as they've been known to reappear weeks later.
is there a size difference in the 2 specimens? usually this doesn't matter, as 2 firefish will instantly join once seeing each other. it is impossible to tell the difference in sex of the specimen.
do you see the more dominant fish chasing, or nipping at the less aggressive fish?
adding firefish is possible. for the most part, they except one another without reluctance. however, one of yours my not have *read the book*. in my 75g, i keep a pair of N. magnifica and a pair of N. decora (purple). let me note that all 4 were added at the same time. however, no problem betweent he 4 has ever existed, and the purple school with the red as if it were natural. from the beginning, my 2 reds were out. a purple joined them about a day later without harm. and i mean it peeked it's head out of a hole long enough to spot the 2 reds, and it cruised over to them. about 5 days later, the other purple peeked out of it's hiding hole, and instantly cruised over to the pack of 3 to make a perfect 4. nowadays, the reds spend more time hovering over my clam shelf, with the purples in a *pocket* just underneath it. they do school together still, maybe about 1/2 the time. i'm presuming the Nemateleotris species puts their differences behind, and figures it's saftery in numbers.
LMK if you have any more quesitons.
HTH
henry