Why do polys flex their dorsal finlets. I've seen them do it when I turn on the lights. When I sit by the tank they'll often swim up to me, sit still and flex them at me. When I feed them I've seen the finlets come out, after water changes. I'll put my finger on the glass and they'll follow my finger and then after I remove my finger they'll flex it. One of my smaller Bichir will swim by my hand and flex her little finlets too. Why do they do this, excitement, fear, dominance, all the above, none of the above?
