If you want to eat fish everyday you can do so as it's safe to eat fish everyday although all you need to do is eat fish at least twice per week to get the health benefits of fish.
Eating fish everyday won't provide you anymore health benefits than eating fish only twice per week but it's not gonna do you any harm to eat and enjoy fish everyday if you want too.
I love fish but I would get tired of eating fish every single day but would do so if it was all I had to eat.