I recently discovered that the tail fin on my male betta is almost 90% gone and the other long fins are split and transulcent looking. I can't see any white or black "fungus" or discoloring around the fins and the smaller fins close to his body (I'm an ametaur fish owner) are round and perfect looking.
He's recently taken an interest in a seashell in his tank and he wedges himself underneath it so I'm wondering if he could have harmed himself some way.
Other than that he's acting normally, he has a ton of energy, he's eating well, and his colors are bright.
I already put in an anti-fungal (I use a preventive every week during the water change) and am planning to get some aquarium salt tomorrow. Does anyone have any other suggestions or idea of what may be wrong?