weird growth

hey guys- i need to know if this is algae or not. it’s kind of hard to identify lol. i just did a HUGE water change and that is what the third pic is... the first pics are a couple days after a 50% water change. fish are doing awesome, even in that weird water so i’m convinced it is some kind...

I noticed this yesterday. White spike looking thing growing on one panda nose. Looks like a baby unicorn horn!!! I cannot find any info anywhere. He's acting fine swimming and eating... 15 gal tank. 3 panda and one dwarf frog. Parameters all good. Zero ammonia and zero nitrites. 10 nitrates. Ph...