fish problems!!!

Question
I am not new to the fish world but have come across a couple of problems since switching to the a new 75 gallon tank.  I have to large filter systems (only one running due to babies), live plants 2 gouramis (1male 1female)1 sailfin molly, 2 silver molly females, 3 balloon mollies, 3 swords, 2 plecos, 3 black mollies and 3 glo fish.  Some of my glo fish have quit eating to the point that they look anorexic. one still looks good and eats fine what are the others problems? they look healthy (other than starving)no noticable physical diseases or parasites.  we have also had a problem keeping the swordtails.  I have checked the water the temp is at 78, and everything seems to be fine i can really take all the advice i can get.  if you need any other info please let me know. thank you

Answer
Hiya.
Firstly, check the tank water for nitrite, ammonia and nitrate. You can buy test kits at fish shops. The nitrite and ammonia should both be 0.0, even 0.1 can be harmful. Do regular water changes to lower it. The nitrate should be under 20ppm. More live plants will help to reduce the nitrate reading.
Feed them a variety of different foods. Feed pellets for the plecs and ordinary flake food for the other fish. Every week, supplement their diet with either live or frozen bloodworm, brineshrimp, daphnia or mysis shrimp. It is good for their digestive system to feed them vegetables, such as cucumber or peas (shell and boil the peas beforehand). Give them a variety of all the food, but do not let them get attached to just one food, and not accept any others. Try several different brands of flake food, some fish just completely ignore some brands.
Stress could be an issue, make sure the area around the tank is quiet, and don't keep the tank lights on for over 10 hours per day.
Good luck, and I hope your fish gets better,
Kathryn