I've had my 29gal tank running for 3 years now and I've only been able to keep the original 2 clown fish. It seems every time I add a fish they die after qt. It could be a few months or a few days. I've tried cardinals, fire fish, corse wrasse, lawnmower blenny, bullet goby, and yellow head goby. I have a fair amount of corals growing well. I tested parameters often and have tested for voltage and the voltage is very low. I have plans to upgrade to a 60gal in the future and will get mostly new equipment other the powerheads. Any thoughts on what doing wrong to not keep fish?