Poor little guy
It should grow back depending on how much has gone. I would keep a close eye out though as he could develop a fungus infection which will eat the tail away very quickly. But if all seems Ok...... melafix is good for healing fins in fish..... try that.
But do keep a really close eye on him.. it can be effected very quickly and before you know it he's too far gone to treat. If you haven't already , I would get both antifungus/finrot and anti internal bacteria in....just to cover the 2 possibilities. Fin rot by fungus (which looks like white fluffy stuff.. then shreds the tail ) Bacterial finrot ( thats leaves blood staining at the edge of the damaged fin)
Oh no!
Really bad news, one of my other Guppies has lost his tail and dorsal fins! He has what looks like a skeleton tail and dorsal fin now... no colour, just spines
What can I do?
Why did this happen?
Treat for finrot... of the fungus variety straight away!!!
What set up do you have...i.e.size of tank whats in it fish wise?
Do you have any type of catfish in there?
Aquarium salt is good for helping to heal fins and reduce stress as well as melafix.
but from the sounds of it hes a gonner .. sorry.
But I would treat to stop it happening to any others.
Yeah you should def. start treatment for fin rot, cuz thats what it sounds like. But i had a male swordie who had lost half his sword and it grew back.