I went to petsmart yesterday to get a battery powered aeration device incase the power goes out during the hurricane, and ended up getting a little redtail there. No one in their tank looked to be sick, all fairly healthy, except for the fact the one shark(the darkest colored one) was bullying all the others. He/she's just a baby, 2 inches at most, I made sure he wasn't the most agressive in the tank there, his temprament seems somewhere in the midline of agressive and docile. Light colored at first, when I brought him home and finally released him in the tank, he darkened up some. I even bought a little cave for him too, but I haven't even put it in the tank yet. He has one rocky cave in there until then, boy did he like that. He gets along fine with everyone, no real bouts yet, very curious and beautiful. He only has to look in the direction of the swordtails fo them to scoot off his turf. I think I've decided to call him, "Triton". I'll have to think of other names for the swordtails too.