I have some questions (this is for upgrading it). how Could i: add a heater (my betta is healthy, but how could i add it, my Kritter keeper hood prevents it) Could i place it on a wood plank bookcase? And where should i have my java ferns? they grown since 6 months and new growth happens. What...

So I noticed that Mojo has a greenish white-ish coloration (Well it looks like color) to him near his ventral fins and it's slowly spreading up his face. He's had a bit of this color ever since I got him like 2 months back and none of my other fish have it. He also looks like he has some scales...