My fish Sonas is fine as far as I can tell, but I really want to know what's going on with this really nasty film that keeps showing up in his tank. Anywho, here's what's going on. The past two weekends I've been out of town with extended family, and each time I come back after a few days to find this icky white substance coating the surface of the water, and anything at or above the surface (like my heater's cord, or decorations). The only thing I can think of its a build up of stesscoat as the water evaporates (we've had 90+F temps out, so I have a fan blowing across the top of the water to speed evaporation and keep the water cool). It hasn't happened in my cycling tank (which has since finished, and is currently housing Sonas), but its happened twice in a row in my 3 gallon. It doesn't seem to have hurt Sonas while he was in the dirty tank, as far as I can tell, but it did really stress him out, and even more so when I'd change the water for him.
Here's as many of the questions as I can answer that are relevant.
What size is your tank? 3 gallons (my 6.6 gallon has no issues)
What temperature is your tank? 80-84F (I can't get it any cooler without using ice cubes)
Does your tank have a filter? No (the 6.6 does)
Does your tank have an air stone or other type of aeration? No
Is your tank heated? Yes
What tank mates does your betta fish live with? None
Have you tested your water? If so, what are the following parameters?
Values at last check:
Nitrate:20ppm (from tap)
How often do you perform a water change? 100% 2 or 3 times a week, depending on the water. I did 100% changes before each weekend trip.
What percentage of the water do you change when you perform a water change? 100%, as stated
What type of additives do you add to the water when you perform a water change? API Stresscoat and a little aquarium salt (for a missing scale issue that's since been resolved, and am reducing the amount used slowly)
I want to repeat that, as far as I know, Sonas is in no danger. I just moved him to a 6.6 gallon tank that has just finished cycling, and is planted, and I've never had any issues with this tank. Its just the 3 gallon that I just moved him out of that kept having this issue.