Fin rot or fin bitter? Help!

[lestranch]

So I am thinking my betta is a fin bitter. I have posted on here before on how to cure fin rot, but I am thinking his shreddy looking tail is because he is biting it. I am religious about keeping his tank clean and all his water parameters in the ideal range, but I keep seeing his back fin looking shreddy and then heal up and then come back.

One of the reason why I do not think it is fin rot because he does not show any symptoms of red or black dots at the ends of his fins. Granted, his tail end is red, but there is no deeper red discoloration. Secondly, when I came into work this morning his tail was visibly a bit shorter and shredded at the tips. When yesterday evening before I left work it was fairly normal and was not at this level of shredding damage.

I read that the bit their fins out of boredom, but I bought him a new ornamant and changed out his gravel. He is pretty agressive and always looking at me to feed him and will jump to get the food when I feed him. I dont know if he is bored at night when I am not here or what.

Please help!

Housing
What size is your tank? 5 gallon fluval chi
What temperature is your tank? 79 degrees
Does your tank have a filter? yes, low flow (could this cause fin rot because it is not filtering enough) (Not sure if he has fin rot though)
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? no

Food
What type of food do you feed your betta fish? Betta bio gold
How often do you feed your betta fish? 3 pellets in the morning and 3 in the evening. Even though he swims and begs me all day for more.

Maintenance
How often do you perform a water change? Normally once or twice a week
What percentage of the water do you change when you perform a water change? 25-50%
What type of additives do you add to the water when you perform a water change? Prime and occasionally aq salt when I thought he had fin rot

Water Parameters:
Have you tested your water? If so, what are the following parameters?

Ammonia:
Nitrite:0
Nitrate:0
pH:7
Hardness:0
Alkalinity:

Symptoms and Treatment
How has your betta fish's appearance changed? Shredded tail at ends
How has your betta fish's behavior changed? No, extremely active
When did you start noticing the symptoms? Pretty much since I got him, most dramatically this morning. Must have happened over night.
Have you started treating your fish? If so, how? yes, prime in his water during water changes and 3 teaspoons of aq salt
Does your fish have any history of being ill? no
How old is your fish (approximately)? not sure fairly young

[lvandert]

Sometimes they also bite because they don't like their big, heavy, beautiful tails. If he doesn't have fin rot I wouldn't worry too terribly much. They will grow back all on their own but the aq salt will definitely help speed that up

[lelei]

Hope he didnt get caught in the filter, can you post a pic..to be sure..you may want to double check the filter for shredded tail, if not it's biting..