my white cloud is not eating, and not swimming well

Question
hi my son got one white cloud fish, read they needed a group of 5 socially, so
that same day, we went to the pet store, picked up a 2 gallon tank and 4
more white cloud fish. they all went into the tank together they've been doing
well until yesterday: noticed the one from the school isn't doing well. he
didn't eat at all, when all others were having a feeding frenzy.  we have 3
females, two of whom of pregnant, and they seem oddly jumpy and
aggressive (maybe babies are coming) about food, etc. i wondered if they had
somehow harassed the male from school (he's also slightly smaller).
the most worrisome thing is that his body is tipped up, as if he's trying to get
air, and he's always at the surface.  can you tell me if there is anything i can
do?  i noticed he was staying away from all the other fish - not usual
behavior, so i took him out and put him in a separate cup to make sure he's
not attacked (I noticed when it was near food, one of the female fish shot up
to where it was to take the food).  is there anything i can do for that fish,
other than isolating it for a time?
please help.

Answer
Well, make sure it doesn not have any signs of a disease, such as twitching, rubbing, white salt like spots, a thick film, swollen body (male only), red spots or lines, and any other odd sight. If not, he is probably being bullied and the tank also may not have enough oxygen for them all. Add a bubble stone if you dont have one, this will add more oxygen and add a nice little bubble line, although it requires an air pump but you can usually get them for about 10-15 dollars maybe even less. Also, if you keep him in the container make sure he has oxygen as well. Other than the above suggestions, make sure to keep an eye on him to make sure he doesnt develop signs of a disease. He may or may not be able to go with the school. The other fish may not like him because he is weaker, although they like schools, the weaker fish are usually weeded out to keep the school strong. Let me know if you need more help.
                                             Rachel A.