my tank is fully cycled, chem levels are all perfect, so we introduced a blueberry painted tetra (which my boyfriend bought and hadn't researched, so didn't know the controversy. don't worry, we won't ever buy another!) and two black widow tetras. the blueberry is actually the most adventurous and swims all over the tank, but the black widows, especially one, are far less active. the one has literally sat in the same corner of the tank & only moved in about a 5 inch radius. the other one is becoming more active,but neither are as adventurous as the blueberry. ii'm thinking that he's probably just scared of the new surroundings, but 'm just worried that he's sick or in shock or something. any thoughts?