i have 4 or should say i had... one died today. The one that died showed no symptoms i came home and he was floating upside down. I believe my nitrites level killed him... The others seem to be doing well. I tested my waters and found my nitrites jumped past 2.0 ppm so time for w/c. but good thing is i have nitrates showing up so cycle is almost complete just gotta get the nitrites to drop. I would watch for normal illness signs, see if he is twitching against stuff, or gasping for air... that type of thing, do you add any stress coat to water during adding of fish?
I think stress may have killed mine as the guy that got them from LFS pulled them out of tank and then reached in net in the air, grabbed one at a time by hand and put in bag... so i think he overstressed the fish by doing it that way... so next time i am going to tell him to to put them back and grab them gently not roughly.