My veiltail Harmonus has surprised me with a terrible looking tail. I went out for one day, left the tank light off the whole time since I didn't want to stress him and his tankmate, and came back at night to see that his tail looked shredded, but only at the edges, and with a hole in it very close to the shredding. I'm not sure what did it.
There is nothing new in his tank, and he's been there for a month with the same things. The filter is external, so I don't think he's getting caught in it. I put aquarium salt in the tank, left the light off to give him more rest, and went to bed myself. I woke up the next morning, and about an inch of his tail was completely gone. It was bleeding and very ragged. I plopped him in a tiny bowl just to make sure it wasn't the filter.
I still can't figure out what's going on. Can anyone tell me what may be happening?
Futher info: water is perfect, temp is perfect. My room is consistently dark, so I leave the hood light on for about 8 hours a day to give them light.
Sidenote: I think he may be biting his tail. I haven't caught him, but this happened after a full [from 10am-10pm] day of flaring at my other betta male. I noticed he couldn't flare his tail fully, and it looked like every time he would flare, he would tip downwards.
And here's one of Caldus, to see if it's finrot or not
Thanks for your help! <3