tropical fish are becoming white and gray

I was playing on my creative world when I decided to get a tropical fish pet. I went to an ocean and spawned a lot to try and get the color I wanted. when I found it, I picked it up with a bucket and it all seemed to be going fine. I made a hole in the sand and got a nametag to put on the fish. but when I placed the fish back down from the bucket, it was white.. I thought that I picked up the wrong fish at first but then when I got another fish, it became white too. then I got another random fish, and another, all of them became white! please fix this bug, I don't know what is going on. fish are my favorite mobs.