Guppy bumps (dorsal fin)

[Kathryn T]

Ammonia, Nitrite and chlorine: 0ppm

Nitrate: 50ppm

GH and KH: off the charts for co-op test strips

pH: 8.2 

Temp: 78.1 f

(Needs water change and will get one shortly, but all consistent parameters for over a year) 

Tank mates: female mystery snail (actively laying eggs) and a solid handful of panda cory's (breeding, numbers are variable) 

This isn't my aquarium, but I can manage it. Are these bumps a couple of eggs from the snail? Or did something else happen? The fish seems fine, moving decently, etc. 

[Kathryn T]

Is this possibly Gas Bubble Disease? Apparently, the tank just had a 30% water change before I arrived, so water conditions may have been higher nitrates than I thought. 

[Colu]

These type of growth's can be caused by viral infection such as lymphocytis or it can be a type of cancerous growth's you could do a course of maracyn2 active ingredient minocycline has proven effective at shrinking some types of lumps and a small amount of aquarium salt 1 table for 5 gallon the salt will help remove any possible fluid buildup in the lumps @Kathryn T

Edited September 26, 2022 by Colu

[Kathryn T]

@Coluthe only new life in this tank in the past year have been the new corys that were born here. Would you still expect to see viral disease crop up so long after the fact? If I think it's just cancer, I don't really want to use antibiotics on baby corys. It did come up very suddenly, though...

[Colu]

Virus can remain dormant for years it's possible that it could be a viral infection what I would do if you can is quarantine him and treat with Aquarium salt 1 table for 2 gallons or you can do salt baths 1 table for 2 gallons for no more than 15 minutes for a couple of days if you don't have a quarantine tank