Lost Tail Overnight

[PrairieSunflower]

Looked in on Firefly this morning and he looked like this.  Just spent the last 2 months (ish) growing in his tail that was eaten up at the pet shop by tetras (his original pre-grown tail in my avatar).
 
I don't know what happened.  With my previous betta it did get its tail stuck and I fixed the filter by putting sponges in the holes and it never happened again.  The sponges are still there to this day.  I can't figure out where else it could get caught.  I've looked over my filter for clues and still no idea.  Nothing else is sharp in the tank, just plants and an arch (not sharp).
 
He has never bitten his tail before that that is unlikely I'd think.

 

[Mamashack]

That's such a shame - he was doing so well too!
Is it you that has the Interpet filter? Seems to ring a bell from ages ago.
If so I have the mini one and my betta's tail has been suffering of late. I have put a black stocking over the inlet grills to prevent him from lolling against the inlets which he seems to like doing for some reason. It's not like he's stuck there - it's like he's chosen to do it since he can swim away at will.

 

[PrairieSunflower]

I think (long since lost the box) it is the Interpet P3.

I will give that a try. 

 

[Wildbetta]

Even though he has not previously been one to bite his tail, this damage looks exactly like tail biting to me.  No idea why he would have suddenly starting biting though.  

 

[PrairieSunflower]

Uh oh.  I hope that is not so.
 
I couldn't manage the stocking over the filter, but I did have craft mesh and managed to sew it in place using yarn.  I hope that is the problem.
 
What things tend to spark tail biting if that is it?

 

[Mamashack]

Stress, boredom, water quality are the ones I can think of for tail-biting. Have you done the stocking test on all the decor for rough edges? Any plastic plants in there?

 

[PrairieSunflower]

Water quality is perfect.  Been checking it daily because someone said the substrate I just added causes ammonia leakage... so far, that doesn't seem to be the case though.
 
I've not done a stocking test but the things in the tank are amazon swords, moss balls, anubias nanas, a rock arch (all curved no edges)... other than those I have the filter and heater... maybe only edge is the heater clip?

 

[Mamashack]

I've just found this article and I think I may just have discovered why mine is doing it. 
http/www.bettysplendens.com/tail-biting---why-do-bettas-do-it.html
My betta tank is next to the platy tank and I used to keep a board in between the 2 tanks. For some reason (can't remember why now) I removed it and I think he's been able to see the adult male platy who he used to fight with when he had a brief spell in the tank. When I say fight, the platy's dorsal fin was ripped up and so were the betta's fins. That's why I got him back in his own tank. The tail and fins have healed with clean warm water, but then they look tatty again.
Could this be the cause for yours, Prairie?

 

[PrairieSunflower]

My tanks are next to each other.  I don't know if it is relevant, but a few weeks back (maybe I month, I forget now) my female honey gourami died.  They used to stare at each other through the glass.  I now have a new female and they don't look at each other.  I don't know, could that mean something?
 
I will read the link.

That gave me a thought.  I've had my betta for several months and he hasn't flared... but he has flared the last few days... in a sort of way like... he starts to flare then goes "oh wait its you"... so sort of a start of a flare but not a complete one.  Maybe that is relevant somehow.

 

[Mamashack]

On reading the article fully I think mine could have blown his fins rather than bitten or torn them. They seem to be split along the rays rather than torn. He and the male platy really were sworn enemies. So he could have been aggressively flaring at the platy through the 2 tank walls.
Have put the board back in place and will see how his fins fare. It will also be interesting to see if the male platy's apparent aggression to his other tank mates settles down. It never occurred to me that he might be venting his frustration at not being able to get to the betta by chasing the others.

 

[PrairieSunflower]

Oh no!  He has lost more tail this afternoon that was there this morning.  Since I covered the filter yesterday it isn't possible that it was that.  Again... so sign of tail bits stuck anywhere... or anywhere at all.  He still even has a partially broken bit hanging on.    I hope this doesn't mean it really is tail biting!

Ah ha!  I have just caught him flicking his right side against things... though... can't see why he is doing that. 
 
 

 

[Mamashack]

Is that what is called "flashing"? Could it be irritation of some sort? Are there any signs of ich or similar?

Have you checked your water parameters since you noticed his fins?
Especially pH and ammonia. Have also read flashing could be parasites tho I hope it isn't!

 

[PrairieSunflower]

Ammonia is perfect, there is a chance pH has changed though with the new substrate.  I shall check right now to see where it is.

pH 6.8

 

[Mamashack]

Is that what you normally run it at?

 

[PrairieSunflower]

Around 7.2-7.4.  I don't check that often as it is quite stable.  But the substrate that I bought did say it would change.