Fuzzy dwarfs can basically be put with any fish that is not small enough for them to eat. They will not harm any fish unless they see them as food. Some of the more aggressive puffers and triggers can sometimes nip at a lionfish's fins and may not be suitable. My fuzzy dwarf is in a tank with a freckled hawkfish, a snowflake eel, and a pair of maroon clownfish. Hope this helps.