Torn/Shredded Tail?

[eclover09]

Housing
What size is your tank? 1 Gallon unfiltered bowl
What temperature is your tank? Its unheated for now -.- Im waiting for my first paycheck to buy them heaters. Its room temperture, around 75 degrees.
Does your tank have a filter? No, he's super tiny Ive been afraid to buy him anything with water flow
What tank mates does your betta fish live with? None, all alone

Food
What type of food do you feed your betta fish? 2 Top Fin Betta Bites and one Hikari Bio Gold, crushed a bit because he's so small even the tiny bites are to big for him.
How often do you feed your betta fish? I feed him three in the morning, once a day.

Maintenance
How often do you perform a water change? A 100% once a week. I had started doing a 100% every other day, but that seemed to seriously stress him out so I cut back.
What type of additives do you add to the water when you perform a water change? I add API water conditionor, with green tea and aloe.

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

To be honest, I've never tested the water. He's in the same kind of water and same room temperture as my three other Betta's, and I've never had problems with there fins before. Could his fins be more sensitive?

Symptoms and Treatment
How has your betta fish's appearance changed? Same coloration
How has your betta fish's behavior changed? Still the same laid back guy.
When did you start noticing the symptoms? This morning
Have you started treating your fish? If so, how? No
Does your fish have any history of being ill? No
How old is your fish (approximately)? He has to be only a juvie, he's very, very small compared to my other Betta'.s

So the story is, yesterday I did a 100% water change in his bowl. He has a rubber like coral plant on the bottom he likes to hide in (virtually impossible to snag fins on this plant) and some jeweled rocks on the bottom (there a little pointy, but if those were the culprit I'd think his long bottom fin would be torn and not his tail). His tail has always been a little tattered since I first got him (his picture on the left) but this morning it's literally TORN. Now, I did use a different water conditionar last night. It's from the same company, but different types I assume? The older one doesn't have the ingrientients on it so im not sure. I only had enough API Water conditionar with green tea and aloe for my three other tanks, so I remebered I had a little left of this Splendid Betta Conditionar and used that. Could this be the culprit? He seems fine, still swimming around and being a little fiesty when I go up to his bowl, but of course I'm worried. Ive had him for two weeks with no issues, it seemed his tail was even growing a bit from the tatterdness, now its torn : (

Here's a picture of his tail

[karlhague]

Too me That looks alot like Tail biting (Him biting his tail)..

To aid the tail healing you could use aquarium salt and indian almond leaf/ or extract..

[Adastra]

You should also be doing more water changes--testing the water will help you determine how much you need to do to keep the water safe. You might find that multiple partial changes per week and one 100% will work better--however, one 100% change a week will not be sufficient. You need to at least be doing very frequent partial changes along with your 100% changes. You should consider getting some live plants like java ferns or java moss--this should help you control the ammonia along with partial changes in addition to your 100% changes.

As far as what's causing the fin deterioration, I can't really tell from the picture. It's not fin rot because it lacks the infected dark edge. It could be a tail blown from too much flaring, it could be biting, but it seems very neat and clean for a bite.

[eclover09]

Well its now turned into I beleive some kind of infection >< This morning it was just torn, but I went out for some errands and when I returned it has become more shredded in appearance and has this like...dark red around the shredded area of the fin. So I rushed out, bought some aquarium salt and changed out his water, added a 1/2 tsp in with his water conditionar then put his bowl in my room since it's the warmest in the house. I was going to buy some anti fungal, but ive read in many forums people don't really use it and jsut buy the aquirium salt. Im going to change his water every other day and keep an eye on it. Is there anything else I should do?