molly sick(urgent)

Question
hi,
i have 2 rosy barb and 7molly(4male and 3female) in my 10 gallon tank. the problem is my black male molly is laying at the bottom of the tank for last 2 days. i also made water change for them. but still it was sitting at the bottom of tank. it came at feeding time and eat the food. ( i think there are No marks on its body) please tell me what can be problem ? what i can do for it ? i think the water quality is OK because all other fish are fine. thanks for help.

Answer
A 10 gallon tank is not big enough for all the fish you have. The molly fish is a brackish fish and needs to have some salt in their water. Since you have so many fish in the tank, you should be doing water changes twice a week. I would remove the molly and place him in your hospital tank. Add salt at the ratio of 1 teaspoon of aquarium salt to 1 gallon of water. He might be suffering from swim bladder disease. Fast him for 2 days and on the third day feed him a cooked shelled pea, then fast again for 2 days. If this does not help, let me know.