Does my betta have fin rot?

[Kassidy47]

My betta(Charlie) has a little, I don't know, half cenimeter squared area at the edge of his tail that looks like its, well, crowntailing. He is a halfmoon. I never even considered it to be fin rot because he is still super active, there are no cloudy white areas on his tail, and he still eats like a pig! I just ignored it until i thought about the possibility it could be fin rot. Do you think it is?

[lvandert]

can you please answer these as best as you can
Housing
What size is your tank?
What temperature is your tank?
Does your tank have a filter?
Does your tank have an air stone or other type of aeration?
Is your tank heated?
What tank mates does your betta fish live with?

Food
What type of food do you feed your betta fish?
How often do you feed your betta fish?

Maintenance
How often do you perform a water change?
What percentage of the water do you change when you perform a water change?
What type of additives do you add to the water when you perform a water change?

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

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

Symptoms and Treatment
How has your betta fish's appearance changed?
How has your betta fish's behavior changed?
When did you start noticing the symptoms?
Have you started treating your fish? If so, how?
Does your fish have any history of being ill?
How old is your fish (approximately)?

[Pearl2011]

Might be finrot, how long has he had it?

[lelei]

Could be tail biting, if there are black edges around it, it's rotting, but if there are no black edges, it sounds like a bite has been taken out of it..

[Kassidy47]

There is no black edges. Although one of my other bettas has dark green edges on his tail, but it doesn't look like they are decaying.... I just noticed it a couple of days ago on the fish in question. He is with two platies but he seemed to get it before I put them in. I had just upgraded him from a one gallon to a 5.5. Could it be that the stress from moving has caused him to bite his own tail?

[lvandert]

you have a betta and two platies in a 5.5?

[Kassidy47]

Housing-
5.5 gallon
79 degrees
No, though I'm looking into getting a sponge filter
No
Yes
2 Platies

Food-
Hikari
3 pellets in the morning and 2 in the evening

Maintenance-
Weekly
100 percent
I just started using tap water conditioner (previously I was just letting the water sit for 24 hours)

Water parameters-
No

Symptoms and treatment-
Barely, just a tiny section of his tail looks spikey
Not at all
About 3 days ago
No
No
I got him about 6 months ago from petco, so I would say about a year.

[Kassidy47]

Ummm uh oh I'm scared now. There are black dots on his tail.....

[lvandert]

ok if his tail doesn't have black edges (check edit) then he's tail biting because he's stressed. a 5.5 gallon can hold 2 small fish (betta and smaller) MAX and you have a betta and two platies. He's stressed as heck because of the other fish. You need to get a 10 gallon if you want to put any other fish with a betta in the same tank.

edit: didn't see your next post. Ok he sounds like he was tail biting from being stressed and then fin rot set in. You need to move him back into his one gallon and change the water every day. You need to go out and either get some aquarium salt and stress coat, or a fin rot medication (avoid bettafix and melafix).

[lvandert]

can you get a picture?