Beta with growth on its head

[Mrscdh1028]

Hi I am new to this forum but have a beta fish with a growth on its head for about 3 weeks. Eating fine, active. I do weekly water changes. I had added betafix initially for a few days but nothing changed. I have searched for anything remotely close to what the growth looks like... I've attached a pic. Can anyone help?

 

[Delapool]

Hi welcome, unfortunately can't zoom in on picture (web software issue here). Does it look lumpy - might be viral? I assume the betta has been in this tank for some time? Is it heated and filtered and no food is getting trapped in that glass pebble substrate to rot?


If you can I would check nitrates as well.