My fish's tail webbing disappearing?

[Emmahlee]

Well, my crowntail betta, Muchacho, overcame fin rot maybe a week or two ago.
But now, instead of the spikes disappearing, the webbing between the spikes is going. Their are no rough edges, just it is disappearing....
is it still fin rot?

Housing
What size is your tank? 3.5
What temperature is your tank? 78F
Does your tank have a filter? Yes
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.

Food
What type of food do you feed your betta fish? Betta Pellets
How often do you feed your betta fish? 1 in the morning and one at night.
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? conditioner, ager.

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

Symptoms and Treatment
How has your betta fish's appearance changed? Webbing disappearing
How has your betta fish's behavior changed? Nope, still his ridiculously active self.
When did you start noticing the symptoms? few days ago.
Have you started treating your fish? If so, how? Nope.
Does your fish have any history of being ill? fin rot.
How old is your fish (approximately)? no clue.

[Emmahlee]

Please help! Im worried. :s

[Sivan]

Pictures?

[Jessicatm137]

I think it is fin rot. Someone correct me if I'm wrong. Are there like pinholes? Or any big holes? A picture would help.