every body I myself found some way to get rid of this problem.
first remember in night the tank must be darker than room , ( not very important
do not feed your fish about 2 or 3 days
do a more cycling water ( more than 10 %) each day, because every one said to me about 10 but do more about 15
drop down the temperature to 27 or 26 celsius. (81 or 79 fahrenheit)
then start to do your regular programs.
feed them and enjoy your fish keeping
in addition you will see more growing speed :P (wow)
hope this helps.