There are over 20,000 species of ferns which are grouped into several different families.
Although not all ferns are toxic some ferns do contain carcinogens. Many also contain thiaminase, an enzyme that depletes the vitamin B complex in the body. Because many ferns are difficult for the non-specialist to ID, we advise people to avoid feeding ferns to their tortoise unless they can positively identify the species and know that it is safe.
We will be working on the Fern section of this website and hope to have more information available on specific species of ferns in due course.