It’s probably the white balance setting the phone is using. Some third party camera apps allow you the change the white balance along with other setting and make it more like a dslr.Its weird with camera's, they seem to pick up the blues heaps more than eyes.
When you look at a tank normally they dont look blue at all - its just the lens on the phone camera, if i use a filter its a lot better.
My son has a DSLR that looks way better (just a lot more work to get the photos on-line)!