You must be sure that you have 0ppm Ammonia... If you will have 0ppm you can feed more, see below... what I had to do.
Laticauda;4744229; said:
Do water changes using Prime, if you have access to it. Treat the whole tank's volume with Prime (1 ml per ten gallons.)
Also, greatly decrease the amount you are feeding, or fast for a day. Keep feeding sparingly until your filter is able to handle the load, then slowly, over the course of a few weeks, increase the number of times you feed per day. Feed small amounts multiple times a day instead of large meals one or two times per day is your ultimate goal.
My rays are pretty well fattened up so they'll be fine if I feed them light for the next couple of days. When I do feed them it's small portions because I know rays have small stomaches but a fast metabolism.
You can check to your tap water. Better check also Chlorine
This chemical is found in most tap water and it is used to kill the bad bacteria in our drinking water. Clorine must be eliminated before entering your aquarium or it will kill your tropical fish.
There are a lots different can remove chlorine.
i use 200L plastic barrel full water. 1 internal filters carbon and sponge. run 24hour then throw water in tank.