Lavender Split-tooth Dorid

About

The Lavender Split-tooth Dorid (Hypselodoris bullocki) is a nudibranch, a shell-less marine mollusk, native to the Indo-West Pacific, where it spends its life creeping along the seafloor in tropical reef environments. Despite being listed here under freshwater invertebrates, this is firmly a saltwater species, and that mislabeling is worth flagging before anyone attempts to keep it in the wrong setup. The coloration is the obvious draw: soft lavender and white tones with the kind of detailed patterning that makes nudibranchs so compelling to reef keepers. Movement is slow and deliberate, as you would expect from any sea slug, which makes it vulnerable to fin-nippers or any fish with a curious, aggressive streak. Tank companions need to be chosen very carefully. The bigger challenge is diet. Nudibranchs in this genus typically feed on specific sponges, and replicating that in captivity is genuinely difficult. This is not a species for anyone new to reef keeping, and even experienced hobbyists often struggle to keep nudibranchs thriving long-term. If you can source the right food consistently and maintain an appropriately calm, well-established reef system, this species is a fascinating subject. But go in with realistic expectations.