Oh, sorry.
Housing
What size is your tank?: About 1 gallon (looking to upgrade soon)
What temperature is your tank?: As of yesterday, 78-80 at all times
Does your tank have a filter?: No
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 so far
Food
What type of food do you feed your betta fish?: Aqueon Betta food
How often do you feed your betta fish?: a couple pellets, two times a day
Maintenance
How often do you perform a water change?: full change 1-2 times a week
What percentage of the water do you change when you perform a water change?: 100%
What type of additives do you add to the water when you perform a water change?: Water conditioner and as of yesterday, aquarium salt
Water Parameters:
Have you tested your water? If so, what are the following parameters?
I've never tested my water
Symptoms and Treatment
How has your betta fish's appearance changed?: Tail is shorter and somewhat white-ish, some trailing fin bits look like they're ready to break off, a few strands on the dorsal fin are gone
How has your betta fish's behavior changed?: It hadn't really changed, though now that he has a heater in his bowl (I bought/installed it yesterday), he is much more lively
When did you start noticing the symptoms?: About 3 days ago
Have you started treating your fish? If so, how?: Yes, I added aquarium salt to his water when I changed it yesterday
Does your fish have any history of being ill?: Not that I know of. He came from petco, and they don't have a track record for outstanding betta care or anything.
How old is your fish (approximately)?: I bought him at the end of the summer, I don't know how long he'd been at petco. I've owned him for 4 months, I think.
Really? That's generally just what he looks like when he relaxes, he tends to alternate between an open tail and a limp tail. I didn't know that meant anything.
I changed his water yesterday and added a teaspoon of aquarium salt. (I let the water heat up, took a cup of his water out, mixed the salt into it completely and then poured it back in. After that I added the water conditioner and placed King back in his tank.) He perked up pretty quickly with the temperature change and has been swimming around pretty constantly ever since.
I read somewhere that fin rot can be caused by poor water conditions, i.e. the water being too cold. When I bought him over the summer, my room was always in the mid to high 70s (we don't have air conditioning) and so the temperature in his bowl was never a problem. However, in the last month or so, it's hard to keep my room at even 70 degrees. I'm assuming that his decline in health was caused by the coldness of his water, as I make sure that his water is very clean. I'm hoping that the rot will clear up with the new heater that I installed (an Aqueon 50 WATT submersible heater, which is working beautifully. I was a little nervous, since it's recommended for 5-20 gallon tanks).