Sounds like you might just have a runt of the school of fish that the LFS aquired
I to have had the same issue with a Cardinal Tetra, I called the LFS back the next
day and explained to them what his behavior was and since I called they said that if
something were to happen and he didnt make it in the next couple a days that they
would credit me with another fish.... MY little Guy Made it.... but if he hadnt at
least I called them to explain and they were willing to work with me in that respect.
Just a thought.....might wana call them up .... let them know....
JUST MY 2 Cents....... I know more heads are better than only ONE BIG ONE..... ( lol )