his tale shredded overnight?

[sharky&george]

My male guppy was fine yesterday looked at him today and a large part of his tale is shredded, it hasnt completley gone just like spiney bits left , fin rot? or another fish? Also female guppy can not maintain balance she is nose down mostly at lower part of tank, any help? Sounds like swim bladder but no others like this!

 

[black angel]

Have you tested the water? How big is the tank, what other fish and how often and how much do you change the water?
If all you can see is the fin rays then its possibly a bad case of fin rot.
Need to know about other fish before i can suggest anything.

 

[sharky&george]

Ok so i have 128 litre and have 5 guppies
15 tetras neon
1 corydora (think that the name)
1 pleco
2 opaline gouramis

All was fine , I added another female guppy and a male guppy on wed! Water fine! I give a big water change every other week but do smaller cleans weekly, if it is a case of finrot it has happened overnight as i have a good look at them all daily and yesterday he was fine!

 

[black angel]

The new fish could have brought in a bacterial disease or like you said another attacked it, you could watch and see if it is being attacked but i would do the following:
For the finrot half litre of warm water and put in 3 teaspoons of aquarium salt and get that to dissolve.
Take the guppy in the net and just dip the whole tail in the solution for a second or three and then return to the tank. Dont put the whole fish in it or he will die, just the fin.
Do this twice a day and hopefully it will kill off the rot and help it heal.
I would hold off from adding meds just now unless you see another fish with similar problems.

The female could be being chased and is exhausted, watch her to see if shes being harrassed by the males. Its also a sign of internal worms, kidney problems or toxic water.