Tiger barb problem

[Fishfinder1973]

Hi all

Looking for advice on 2 tiger barbs that have a problem.

I have a shoal/school of 12 tiger barbs and last week I noticed 2 of them swimming in a 80 degree downward angle.The other 10 barbs are fine,but these other two have lost the bottom fork of there tail fins,lost there pelvic fins and their anal fins.I think it’s been other fish that have nibbled their fins,but I don’t understand why only two of the group have began swimming like this.I keep a close eye on water parameters and ammonia and nitrite seems fine,although my nitrate is between 20 and 40.
Could this be a case of the shoal turning on what fish they regard as weak.
Unfortunately I don’t have an isolation tank yet.
Any advice would be great and if I can figure how to put a photo up,I will.
Thankyou.

Ian

 

[Autumnsky]

How long have you had the tank running, and how long have these guys been in there?

Do you know your pH?

 

[Fishfinder1973]

How long have you had the tank running, and how long have these guys been in there?

Do you know your pH?

Thank you for the reply Autumnsky.

I’ve had fish in the tank since mid to late March.All have been healthy,swimming normally and eating,that is.
My pH is 6.6,and has been more or less on that since I cycled the tank.when I say more or less,it can drop to 6.4,but no less.
Ammonia has been zero,along with Nitrite for 100% of the time,until yesterday that is,but I am pretty sure moving my hob filter caused this,as I had to search inside the filter for my zebra plec,and in doing so,i unfortunately released some of the dirt into the tank.This happened between putting the post up and your reply.Bad mistake,but i did a 40% water change and will be doing another 20% today.
The barb problem began last week,and whatever happened,happened through the night.
It’s a tough one to call,but I had to ask,just in case i missed the Forrest because of the trees.
Thanks again for your reply.

 

[Fishfinder1973]

Thank you for the reply Autumnsky.

I’ve had fish in the tank since mid to late March.All have been healthy,swimming normally and eating,that is.
My pH is 6.6,and has been more or less on that since I cycled the tank.when I say more or less,it can drop to 6.4,but no less.
Ammonia has been zero,along with Nitrite for 100% of the time,until yesterday that is,but I am pretty sure moving my hob filter caused this,as I had to search inside the filter for my zebra plec,and in doing so,i unfortunately released some of the dirt into the tank.This happened between putting the post up and your reply.Bad mistake,but i did a 40% water change and will be doing another 20% today.
The barb problem began last week,and whatever happened,happened through the night.
It’s a tough one to call,but I had to ask,just in case i missed the Forrest because of the trees.
Thanks again for your reply.

https://share.icloud.com/photos/0RomCZ44Ph-fjbGDVTvneDXYw
Hopefully you can see the photo