We had a hermit crab once.
2.75" x 2.75" embroidered patch (but we always recommend sewing it on for longevity)
Our patches iron on best to natural fibers, like cotton or denim, and will not adhere to synthetic fabrics.
Here are a few handy tricks for easy ironing of our patches:
1. Set your iron to the setting matching the fabric you are adhering to (cotton, linen, etc.)
2. Lay the garment flat and put a cloth over the area of the item where the patch is to be applied. Place the heated iron on the cloth and press down firmly for 8 seconds to heat up the garment.
3. Place your iron-on patch on the pre-heated area, put the cloth on top of the patch and press down firmly for 8-10 seconds with your iron. Turn garment inside out, put a cloth on top of the patch area, and press down with the iron for another 5 seconds.
4. Remove the iron and cloth, set the item aside and allow it to fully cool before handling.
5. Show off your sweet new patch to all your friends!