Something pulsating on the side of my betta

[PimWiz]

So i've had this betta for about a month now and recently i noticed he started to become skinny fas and becoming more and more lethargic,now i saw something transparrent on his side,at first i tought maybe he impaled himself somehow but it pulsates

https://imgur.com/a/CLQIKnZ

 

[Andy Sager]

That appears to be Anchor worm. There are a few ways of treating. 1) a bath of Potassium Permanganate. 2) Dimilin will kill anchorworm. 3) Coppersafe. 4) Cupramine. #3 and #4 are copper based so best used in a separate hospital tank.
Another option if there is only one worm is to physically remove the worm with a pair of tweezers then watch carefully for post infections. There may be more worms in intermediate stages that you cannot see yet so you'll have to keep a sharp eye on the fish for reinfection.

Hope this helps

 

[PimWiz]

That appears to be Anchor worm. There are a few ways of treating. 1) a bath of Potassium Permanganate. 2) Dimilin will kill anchorworm. 3) Coppersafe. 4) Cupramine. #3 and #4 are copper based so best used in a separate hospital tank.
Another option if there is only one worm is to physically remove the worm with a pair of tweezers then watch carefully for post infections. There may be more worms in intermediate stages that you cannot see yet so you'll have to keep a sharp eye on the fish for reinfection.

Hope this helps

In the worst case scenario where I can't save him,it it possible for the worm to lay eggs somewhere and infect the fish that will populate the tank?

 

[Andy Sager]

In the worst case scenario where I can't save him,it it possible for the worm to lay eggs somewhere and infect the fish that will populate the tank?

Yes. The longer the worm is on your fish, the greater the chances it lays eggs which when they hatch, will be in your tank as larvae until they find another host fish to attach to.