Very Swollen Leg all of a sudden?

[PearlTooth]

Https://imgur.com/a/3RoDfn4

His leg puffed up all of a sudden despite his good previous health, I quickly tubbed him but do not know what to do, help appreciated.

 

[GemCityAxolotls]

Furan 2 treatment, if it’s not too late. Follow instructions as directed on the box, but use half dose for axies. So 1/4 packet per 5gal. Repeat every 24hrs. Only mix as much as you need for that day, as the medication loses its effect 24hrs after mixing. Treat in a tub, not the tank. Furan has been known to crash cycles.