HUGE clean-sliced chunk of tail MISSING!?! :(

[goldentryst]

When I left the house at 10AM, my beloved Fishy was all good to go.

...Around 8PM my mother calls me and tells me there's a 'slice' in Fishy's tail. I thought it was probably a minor cut that split his tail into two, so I told her it'd be okay and I'll check it out when I get home.

Right now it is 7:15AM, and I'm shocked with what I see.

First, the pictures:

Fishy Before:



[Sleeping] Fishy (Now):





I am so shocked and confused and worried. What the heck happened to the middle portion of Fishy's tail? He's a delta with fins that like to get a bit ruined now and then, but I've never seen anything like this before. It doesn't even seem like he bit it...

With the picture of the aquarium in its whole, could anyone surmise what could have happened in my absence? Supposedly Fishy is still acting the same according to my mother: happy, active, perky, hungry, etc. He's still sleeping as of now so I'll have to wait and see if that's true.


ETC:
- 81 degrees
- Whisper10i
- currently undergoing AQ salt treatment; today is the 8th day and I plan to stop at the 10th. Will throw out all the water in the 10gall and replace. New carbon filter too.

Something different was this:



That's not a bubble nest, I'm sure. I think those bubbles came from the little stack of yellow boba straw which I used along with a tape and rubber band to slightly hinder the filter's flow a bit more. This is the only thing which I can point out as different. I put this in about 1-2 days ago?

Thank you so much for any help!

[goldentryst]

Okay, so he just woke up a few minutes ago :] I turned on the aquarium light for him and fed him two pieces of freeze-dried bloodworm. He's acting totally normal, and if anything he kinda seems... well, it looks like swimming is more comfortable for him without that heavy chunk of a tail attached to his body. o.o

I also noticed that there are little bite marks at the top and bottom part of his tail. Could it be that he's a tail-biter? I suppose he has had a minor history of it. Though he does not seem unhappy and exhibits all the traits of a healthy betta fish. Not to mention he has a 10gall heated tank and frequent water changes all to himself o.O

Maybe the tail that weighted down was getting on his last nerves?

I'm just speculating possibilities, but I would appreciate any comments. XD I really want to know why this happened, and so perhaps I can prevent it from occurring again in the future

[Luimeril]

he either ripped it on something, or he's bitten a chunk out of his tail. longer finned bettas often do it due to stress or boredom. in your case, it could be either or both. try adding a few more plants for him to swim through and hide in. silk is alot better than plastic, because plastic can often be sharp and rip their fins up. :V i had that happen to my oldest, a veil named Cup, before he passed. ripped his fins to SHREDS. :T
also, rearrange his decor at every water change. that often gives them something to do, as they explore their "new" territory.

[vilmarisv]

Do you have anything covering the intake of the filter?
Those filters have a pretty strong current and the baffle on top will not affect the suction in the bottom.
Had a HM a loooog time ago who's tail was turned to shreds with one of these filters because he would go behind it.

[goldentryst]

I apologize for such a late reply! Thank you Luimeril and vilmarisv for taking the time to respond! My boy is no longer mutilating his own tail.

I do believe it was because of that insane filter. I have blocked it with a makeshift... 'dam' sort of thing constructed out of the top of a large Sprite Soda bottle. The water current now travels directly down from the lip of the filter [and does not disturb the entire tank as much], and although it may not be 200% perfect I do feel that Fishy is a lot more comfortable. Before I blocked the filter's flow I noticed he did seem to be putting in considerable effort to swim. It's a lot better now.

Thank you again. :]



...Now the only thing that's happened recently is he's missing a scale (?) around his head, but I'm thinking he may have bumped his head on something maybe? This happened around the time before I blocked the filter. Poor guy. I do a bunch of water changes though, so I do think it'll heal over soon.