My Betta is dying :(

[Tazo]

Is it a peace lily? If so, the leaves need to be above the water, otherwise it will slowly rot and die, releasing ammonia.

Could you please fill out the form that is stickied at the top of this board? It'd really help people to help you.

[Cormasaurus]

Housing
What size is your tank?
5 gallons
What temperature is your tank?
approx. 80 degrees
Does your tank have a filter?
yes
Does your tank have an air stone or other type of aeration?
yes
Is your tank heated?
yes
What tank mates does your betta fish live with?
none

Food
What type of food do you feed your betta fish?
bloodworms and betta pellets

How often do you feed your betta fish?
twice a day - some in the morning before I leave and some when I get home. I find it keeps him from biting too much if I feed him smaller amounts twice a day.

Maintenance
How often do you perform a water change?
10-25% once a week depending on tank conditions, and 100% every 2-4 weeks depending on the tank conditions

What percentage of the water do you change when you perform a water change? Shoot, I answered that in the above question before reading further.

What type of additives do you add to the water when you perform a water change?
Water conditioner and stress coat, because he usually bites when I change the water no matter what the temperature is or the setting of the decorations

Water Parameters:
Have you tested your water? If so, what are the following parameters?
I have not tested it and do not know where to get the things required to.

Ammonia:
Nitrite:
Nitrate:
pH:
Hardness:
Alkalinity:

Symptoms and Treatment
How has your betta fish's appearance changed? It hasn't, unless he has gotten more red, which I cannot tell.

How has your betta fish's behavior changed?
He was lazy and laying at the bottom of the tank and could not eat.

When did you start noticing the symptoms? Yesterday

Have you started treating your fish? If so, how? I performed a water change and added aquarium salt this morning, but he was fine last night after I fed him.

Does your fish have any history of being ill? No, he just bites his tail.

How old is your fish (approximately)? I would guess he was born sometime in the spring. I got him mid-May.

I filled this out because it was requested, but Pippin is fine now. He's swimming around in his favorite corner every time I enter my room. :D

I don't know what kind of lily plant I have. I bought it at wal-mart and it has red and green leaves. I cut the leaves that don't grow past the water level off of the plant after a week or so of them staying the same length.