Film on water surface

Question
Hello, my beta is in about 1 gallon or so of water and I used distilled or drinking water on him.  I've had him for several months and I recently purchased a female one also.  I keep them at different ends of the counter, I don't think they see each other but recently they started getting a film on the water surface which when I wipe it off it seems to be a white substance.  Do you know what that is?  Thanks, Rachel

Answer
Hi Rachel;

It's probably either dust or oil from the fish food. You might cover one of them for a couple of days (with a small hole or opening to let air in) and see if it looks better than the other. If so, I would say dust. If not, it's probably from the food. Sometimes the fish themselves put out waste particles that float like that too.

It is best not to use distilled water for your fish. It lacks minerals your fish need. Bottled water, spring water or just plain tap water with a water conditioner is just fine. Be sure whatever water you fill it with is the same temperature as the old water to prevent shock.

At Your Service;
Chris Robbins