> hey i'm pretty new to the hobby. long-time admirer, short-time fish-keeper. i've got a 5-gallon FW that's doing "swimmingly" if you know what i mean, but i'm trying to set up a 10-gallon SW and i have had almost no luck whatsoever. [ yeah the tanks are small but that's because i'm renting. in order to get bigger tanks i'd need to get renter's insurance and that just doesn't fit in the budget ] i've been trying to cycle my 10-gallon but all the fish die. i started with a pair of yellowtail damsels, and the one beat up on the other (nipped its fins to shreds) that i gave the nipped one away to a better home. a couple of days later i noticed rising nitrite levels, although they were still well within reasonable limits--a good sign. the next day, my damsel was upside down on the bottom of the tank. i got a green chromis to keep the cycle going. it died within 48 hours. all measurable water parameters read normal. i replaced the green chromis with another (this is from Petco, so it's not costing me extra money at this point). it died within 24 hours. water parameters normal. i replaced it with a pair of green chromis. they died within 24 hours. all water parameters read NORMAL! temperature is steady at 74 degrees F. specific gravity is steady at 1.023. inspection of the filter reveals nothing unusual--it looks fine. i have been careful to acclimate all these fish both temperature-wise and salinity-wise before introducing them to the tank. i have observed a good feeding response from almost all of them, and they still died within 24 hours. i do have a starfish in the tank (see my other thread in the newby section), perhaps it is somehow responsible for all this? maybe it is some weird strain that releases toxins into the water? as of right now i refuse to put any more fish in the tank. i suppose i can continue to raise the starfish, but overall i am very depressed. i have read tons of info on how to properly set up everything and nothing has worked. completely ignorant people who just buy everything at once and slap it all together have more luck than me! #Q$%@%#^ what is wrong with the tank??? the only thing i can think of is that i had to wash the tank before i set it up. i did this with soap and bleach. i read that you have to be careful when you do this to make sure you wash out all residue of the bleach, and i was pretty darn sure i washed it all out! i rinsed and scrubbed the tank many, many times. perhaps this is the problem? or perhaps there's some kind of mystery disease/bacteria floating around in there? some sickness that the starfish introduces into the water? but the starfish came from a tank with fish that are just fine....grr i have no clue. i'm very depressed and disappointed right now. i have tried very hard to do it right and couldn't have failed more utterly. please help!