This is my first time keeping fish and last night I noticed a discoloration on one of my female guppies who just gave birth. I could not find anything similar to it online except maybe a fungal or bacterial infection, although it is not slimy or fuzzy in appearance. It almost looked like she had been rubbing hard on her left side.
This morning the discoloration is still there and it looks like she is developing a small white spot on her left pectoral fin. It is small and not raised but I am still concerned. She has been breathing heavily and keeping mostly to the bottom of the tank. She is still active and is feeding, but less than the other guppies in the tank. Does anyone have any ideas what this could be and what the best course of action should be?
The 30g tank has been running for almost three weeks and I have checked the water parameters about every other day since I started. They are:
Nitrate: 0-5 (it is heavily planted so I am thinking that is why there is no nitrate buildup).
water changes: 5-10g every 3 days
I have lots of plants in the aquarium and a total of 5 guppies (and 20 fry as of Friday) and 9 spotted blue-eyes. Since I added my first fish I have not had detectable levels of ammonia or nitrite, although the males are constantly chasing her around which may be stressing her out.
I appreciate any advice. Thanks