Taimur85;529826 wrote: So i've had my tank up and running for a little over a year. It's a 75 gallon, 6 t-5s, ehiem filter, all levels are stable (ni- 0, am - 0, ni - 20, ph - 8.3). For some reason, any new fish I add keep dying. I currently have a yellow tang, three clowns, two small blue damsels, a mandarin goby, and a blenny. Pretty much every sand sifting goby I have bought dies within a a few weeks, any other fish I have added survives for a while, then dies as well. Do you think my fish are just super aggressive, or is it a fundamental problem? Additional info is probably needed, so just ask. Thanks!