My first tattoo had crap ink. At the end of 20 years it had all but completely faded away, it was done while I was in Okinwawa Japan in the early '80s.
Now the inks are much better & they stay bright too, I found a great artist & had her do a redo on it. I was so happy with the result I got a few more. Just make sure that you get an artist who has done reptile tats before & is comfortable. My person here specializes in Celtic, tribal & Asian stuff.
If I ever add a reptile tat, she told me she would recommend a guy she knows for that... gotta love someone who's so good at what they do & honest they would do that. Definitely see a sample of work & get the right person so you'll be happy with the result.