Haddoni should only be in tanks with anemonefish that accept them as hosts or fish who are otherwise associated with anemones like certain cardinals (Banggai for example), Dascyllus damsels (especially the Dominos), and a few other.
I lost fish to my haddoni (I have 7 of them in 3 tanks) who had no issues being around giganteas.
I think what makes haddoni so dangerous to fish are their short tentacles that do not move. It makes the anemone look less threatening than those anemones who's longer tentacles wave in the flow and signal danger.
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