Fin rot or damage from decorations?

[Bcake86]

Hello,
I am wondering how I can know if the damage on my bettas back fin is due from tail rot or from plastic plant decorations? I have a 10 gal tank with heater and filter. It has 1 betta 2 platy 1 zebra snail and 2 ghost shrimp. Am I overstocked? He used to be in his tank alone with just a few decorations and never had a problem. Now I notice part of his tail seems shorter than normal.

[shellieca]

Does it look like a tear? Are there black edges? Can you post a pic? It is possible one of your other fish nipped him. What about your filter intake? That can suck the fins in & damage them. What is your water change schedule & how much water do you change?

[Myates]

Biting tend to have curved edges.. C or U, even a V chunk missing out of it.
Splitting/shredding looks like you would think it would.
Fin rot you will see the edges of the damage/fins blackened, sometimes a bit see through black, sometimes it would see as if it is "flaking" off.

[Bcake86]

It's hard to tell bc he's a crowntail, but the tips seem to be loosing color. Sounds like rot? What's the best way to treat it?

[Nothingness]

see the disease thread for how to treat common ailments