Gourami blister

[Laurelp]

I moved my powder blue Gourami from his 60 gallon tank to the 20 gallon tank about a week ago because he was being really aggressive with the dwarf Gourami. He is now in a 20g tank with 3 African dwarf frogs, 6 male endlers, and 1 Dalmatian Molly. He developed this blister over night and it just broke. I can’t seem to figure out what it is. Lymphocystis? I have a photo here of the blister and two minutes later after it broke. Any thoughts?

 

[Laurelp]

To note- I just got new fish yesterday and they are currently taking up the quarantine tank.

 

[Colin_T]

It is not lymphocystis.

It could be the start of the gourami iridovirus. If it is the iridovirus, there is nothing you can do except keep the fish well looked after and hope it fights off the virus.

Do a 75% water change and gravel clean the substrate every day for a couple of weeks. This will help to dilute any nasty stuff that might be coming out of the blister or the fish.
Make sure any new water is free of chlorine/ chloramine before it's added to the tank.

 

[Laurelp]

That’s what I will do. Thank you for the input! Fingers crossed.