This is a female betta that I've only had for about 2 weeks. Tonight I noticed this whitish area on the back of her head - she moves so fast that I couldn't tell with the naked eye if it was just a loss of color in that area, fungus, or something more sinister. So I took pictures. Looks like it's not a simply loss of color I don't think. What does it look like to you? Fungus? Something else? Or do I have to worry here about columnaris, or worse, fish TB? Gave you 3 pictures - the middle one is a close up of the first pic.
Some info: She's in a 5 gallon (alone). She is eating really well currently (eats a staple of Hikari Bio Betta Gold but also gets brine shrimp, krill, bloodowmrs, and peas occasionally). She was really active - always at the front of the tank. She's still active, but isn't always at the front anymore - sometimes I have to look for her if you kwim. Then all of a sudden she'll see me and swim right out from wherever it is she was. I used mature media from a well established tank to seed her new filter (which is a Hydro II sponge filter powered by a Whisper air pump) but it didn't work "immediately" like I'm used to and I basically ended up with a mini-cycle - she had about 4-5 days of ammonia readings - never higher than about 0.75 - usually more around .50. I did 50% water changes each time she was over .25 (usually once a day). Ammonia is now gone (to 0) and nitrites are ever so slightly above 0 (no where near the 0.25 color - I'd guess they are like 0.10). Tests, btw, are API liquid. pH is somewhere around 7.6, water is moderately hard. She has a heater, and the water is currently 79. There are no live plants - just silk.
Here are the 3 pics:
Some info: She's in a 5 gallon (alone). She is eating really well currently (eats a staple of Hikari Bio Betta Gold but also gets brine shrimp, krill, bloodowmrs, and peas occasionally). She was really active - always at the front of the tank. She's still active, but isn't always at the front anymore - sometimes I have to look for her if you kwim. Then all of a sudden she'll see me and swim right out from wherever it is she was. I used mature media from a well established tank to seed her new filter (which is a Hydro II sponge filter powered by a Whisper air pump) but it didn't work "immediately" like I'm used to and I basically ended up with a mini-cycle - she had about 4-5 days of ammonia readings - never higher than about 0.75 - usually more around .50. I did 50% water changes each time she was over .25 (usually once a day). Ammonia is now gone (to 0) and nitrites are ever so slightly above 0 (no where near the 0.25 color - I'd guess they are like 0.10). Tests, btw, are API liquid. pH is somewhere around 7.6, water is moderately hard. She has a heater, and the water is currently 79. There are no live plants - just silk.
Here are the 3 pics:


