Tail Biter of Fin Rot?

[beatlesmania]

Hey so my boy Popper is having some issues. so here's the info:

Housing
What size is your tank? 3.7 L
What temperature is your tank? about 70-75f
Does your tank have a filter? no
Does your tank have an air stone or other type of aeration? no
Is your tank heated? no
What tank mates does your betta fish live with? none

Food
What type of food do you feed your betta fish? somedays I give him flakes and other days he gets pellets.
How often do you feed your betta fish? once a day.

Maintenance
How often do you perform a water change? once 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

Symptoms and Treatment
How has your betta fish's appearance changed? his tale (pics)
How has your betta fish's behavior changed? he seems fine but every once in a while he swims around eractically and crazy like.
When did you start noticing the symptoms? swimming-yesterday, tail-today
Have you started treating your fish? If so, how? no
Does your fish have any history of being ill? yes
How old is your fish (approximately)? a month? or just over a month.

He's eating normally, swimming normally except for the occasional craziness, and every once in awhile he's flares his gills. his color hasn't changed, it' just his tail.
Now, the last time I posted on here was also about his tail because it was scrunched together and not spread out. I was told to feed him twice a day, which made him worse and almost gave him ammonia poisoning. so please lets not have another repeat of that.

Thanks.

[Silverfang]

Not exactly why you posted, but I have to say, it looks like he's got some major fin curling or kinking. I have heard that these can be cause by fins healing improperly, or suffering some some injury.

It could be biting or blow out, but I'm more inclined to think that his fins/tail are separating from the curling. Does it appear that the fin is "growing apart" for lack of a better way of putting it? I have a boy who has a similar occurrence.

I'm not sure if there is anything that can be done. Hope someone can offer something more insightful.

[beatlesmania]

Sometimes he does spread his tail out more than he used too. but even when he did spread it out before, it certainly didn't look like this.

[Silverfang]

the best way to determine if it's rot, is are the edges discoloured? are they reddish or black? Dark and crusty? Just keep the water extra clean, all I can really suggest.