Gymnothorax castaneus is (very) poisonous and the poison can kill you under circumstances!!!
If you want to keep Gymnothorax castaneus, inform yourself about the poison and its effects before buying. Keep a note with the telephone number of the poison emergency call and all necessary information about the animal next to your aquarium so that you can be helped quickly in an emergency.
The telephone numbers of the poison emergency call can be found here:
Overview Worldwide: eapcct.org
This message appears for poisonous, very poisonous and also animals whose poison can kill you immediately. Every human reacts differently to poisons. Please therefore weigh the risk for yourself AND your environment very carefully, and never act lightly!
(Jordan & Gilbert, 1883)
Lives in rocky, boulder strewn areas and walls. Lurks in holes, crevices and dark recesses during day; forage in the open at night.