Feeding just normal fish food, some flake (Wardley Essential Flake) (for the smaller fish), floating pellets for the bigger fish (Wardley goldfish
Floating Pellets), algae wafer for the sucker fish (Hikari Tropical Algae Wafer) - about 1/2 an algae wafer a day, occasional frozen blood worms as a treat (no more than once a week).
I don't know if it matters, but as mentioned before, the tank is always crystal clear, I can't remember the last time I cleaned the glass, I vacuum the gravel maybe once a month (no more often). I pretty much just change the filter cartridges on my Whisper 30-60 (the double waterfall one) - I do add extra carbon and zeolite to my falters. The filter is rated 30-60 gallons and I have a low-med bio load, so I think that's why the aquarium is always crystal clear. (I hope I'm not getting off topic here). The aquarium is well established, about 2+ years, and has never crashed. My gold fish
are actually about 3+ years old, I had a very small 35 gallon pond I could no longer keep, so I bought this tank about 2 years ago and transferred my fishies to this.
Thanks for the bleach tip, now I know I can do that and not be worried. I'll preserve the filter "Bio sponge" things in tank water while I do the cleaning, so they don't lose their good bacteria, and I'll clean the filter box using bleach. But I am still curious how the white mold ever started? and is it "bad"? (for me OR the fish!) Anything I can do to prevent it in the future?
Also tested the thank for everything yesterday, PH, ammonia, Nitrate, Nitrite, Salt - everything was good except for Nitrate was high (as always), and salt was just and tad high (corrected with my normal partial water change). They are "pond" fish so I do add pond salt (as they have always been accustomed to).