Hi, so this is my first post, so I'm sorry if it's a bit out of format haha.
I got a new male betta fish about two months ago. When I got him initially, he was extremely vibrant in color - bright red fins, bluish green body. Crazy, deep, colors. Super striking.
For about a month and a half, his color stayed consistently the same. He's been in a 15 gallon tank, heated and filtered. Small water changes regularly, with API water conditioner. 4 plants. He's very active, his water is about 81 degrees at all times. He's interactive, he'll follow my finger around the side of the tank, he eats as much as I'll give him (I feed 2 pellets a day, 2 times a day, or sometimes all 4 at once in the morning when I have work all day) he's swimming well, his fins are not rotting or tearing (he did have a little tear about two weeks ago because he swam into his filter, but I put a mesh cover over it and it has healed up since.) He lives alone, his tank is clean, no algae, never been housed with anything else.
For all I can tell, absolutely nothing is wrong with him or his living conditions.
Now, here is where things get odd.
When anyone approaches the tank lately, myself included (even when I feed him), the color rapidly - and I mean visibly rapidly - drains from all over his body, he becomes almost ghost-like and pale. He will remain colorless - but still active and playful and interested - and when you get far enough away from the tank, in a few minutes, ALL of his color is back.
When I first saw him so pale I got worried about the water quality, and I took him out and put him in a 1 gallon for holding while I did a 50% water change on his tank. Confusingly, he regained all of his vibrant color while sitting in his holding tank. When I let him back into his 15 gallon, he kept his color all night, and swam about content as ever.
As of now, the color comes and goes. Most frequently, he is ghost-like and pale, and it really is sad to see. I don't understand how he could be sick when he is behaving so healthy, happy, and curious!
Is my betta getting sick? Has anyone else had a fish with a case of vanishing color syndrome? Is there anything I can do to bring it back to normal? :-?
Sorry for the long post, I am really really confused. :-(