"slice" In Oliver's Tail

[Morphkid03]

Noticed today Oliver has a nice long cut on his tail fin... It's hard to photograph because it is almost always hidden by his dorsal fin- it's about a 3 inch long perfect slice of less then 1/8 of an inch of tail fin. He hasn't really changed behavior because of it, not signs of illness or anything, and seems ok. I have no idea how this happened- nothing sharp enough in the tank to cause such an injury. How should I treat it, if at all?
Water stats are fine, he lives in a 5 gallon with 3 cory cats (I know, slightly overstocked, but I do more frequent water changes because of it, not to worry)

 

[LauraFrog]

This just happens sometimes, especially if a betta gets caught in a filter current (and some of them will do it even with a gentle current, they will stay under it all day).

Treat with Melafix. This won't harm the corys or the bacterial colony and it will help it to heal faster.

 

[Honeythorn]

Yep, as above. Duncan gets them sometimes too. He LOVES to squeeze between things. I have no idea how he does it or what on because there is nothing sharp in the tank. It seems to be just one of those things. Melafix and very regular water changes soon sorts it out don't worry

 

[LauraFrog]

LOL! I have a fin chewer, so I guess my silly boy Heatstroke pretty much tops the list for bad habits.. he's a veiltail, but his tail is rarely any longer than a plakat's. I've given up. He seems happy enough otherwise, and no matter where I put him, he still does it.

They've all got quirks though, like the playing in the filter current bit... one of mine lives in a rounded tank and the reflection distorts, so he likes to sit in front of the glass and move backwards and forwards to watch the shape of the reflection change... it's so funny watching him.