Blowing his tail?

[Styx]

My delta tail's tail fin is just shredded. He is tanked by himself and is in heated water. It's not fin rot. Is he blowing his tail? Why and how do I stop this?

 

[littlefishie]

It could be blown if he's been flaring too much, but he also could've caught it on a plastic plant or had bits of it sucked into the filter.

A little bit of salt [1 tablespoon per 5 gallons] and some Melafix will help.