artists_beware | Advice wanted - Premade design used for tattoo (Reply)

I've never had this particular situation come up for me before, so I'm not entirely sure how to proceed with it.

I received an email today about a tribal-inspired rabbit image that I have posted to my DeviantArt account. The email reads:

Hi Syn,

I hope you are well.

This is just email to let you know that I'm really interested in getting your tribal bunny as a tattoo but it won't be on display unless I'm topless. :p

Just wondering if you would be okay with this? (I'm not familiar with how people deal with artists and their artwork they wish to have tattoo'ed, sorry!) but I just wanted to ask how you felt about this and let you know that I will not be taking any credit for your artwork.

But on another note I would not be surprised if I wasn't the first person to want it as a tattoo :) really do love the design..

It will however be in the memory of my pet rabbit that I had for over 12 years. And I would love to have this as a tattoo.

Hope to hear from you soon

Now, this is where I'm baffled on how to proceed. I've done tattoo work with people before, but it's always been for custom work - the designs I've made have specifically been for the commissioner. This is the first time that I've been approached about using a pre-made design.

I do plan on insisting on full artistic credit for the design (though I'm not sure how to go about ensuring I get it), and I don't feel comfortable letting the design go without compensation. However, I don't know what would be appropriate as a royalty - should I give just a flat amount or a percentage based on the quote for the cost of the tattoo? Also, how would I go about ensuring full credit - would that be something I discuss with the person's tattoo artist directly?

Any feedback is appreciated.

ETA: So, firstly - thank you to everyone that left advice and feedback, I greatly appreciate it!

I've sent a response to the person that contacted me, which reads as follows:

Hi Millie. It's lovely to hear that you're interested in my art!

I've been considering your email over the course of the day and I would like to offer a proposal to you. You mentioned that you would be getting this tattoo in memory of your pet rabbit and I wonder, instead of using a pre-made design, if you would be interested in having a custom design made instead. I have done custom tattoo design work in the past and, if you are interested, would be delighted to work with you to create a design that's more personalized to you and the bond you shared with your companion.

I look forward to discussing this idea with you further.

Syn

Hopefully the person is receptive to the idea of a custom piece. :)