Hello I recently purched three yellow tangs as some of the last fish to get introduced to my tank. the tank is a 225 reef approx 3 months into new setup. fish were introduced about a week ago and it seems one of the tangs is developing a lump at the back of the lateral line. fish is eating well and nobody is picking on him. just wondering if this may be stress related or parisites...stocked with the 3 yellow tangs are 1 powder blue tang, 1 scopus tang, 1 blue hippo tang, 2 b. cardinals, 2 black clowns, 2 orangw clowns, 1 diamond goby, 9 green chromis, 1 cucumber, 2 sand sifting stars, tonga nesariuth snails, mexican tubo snails, 2 small hermit crabs. everything else is doing wonderfull thanks