I have a 20 gallon hex tank. I set it up a little more than a week ago with live sand. A couple days later (now exactly one week ago) I got two fish (yellow-tailed damsels I think) that the fish store characterized as starter fish good for cycling the tank. Also added about 20 lbs of live rock.
Everything seemed to be going fine. Fish seemed active all week. Yesterday morning I took out the Penguine power head and put in a Koralia nano and Koralia 1. Yesterday evening, one fish was on the bottom on its side. This morning both appear to have died.
I have a several years beyond indicated expiration date Wardley test kit. According to that, Ph is 8.2 (79 deg), Ammonia is 0.25 ppm
, nitrite undetectable, and nitrate at 20 ppm
. Specific gravity is between 1.021 and 1.020.
I assume the tank could not have cycled within a week, right? So perhaps the test kit (b/c it is so old) is giving incorrect results and the ammonia or nitrite levels are actually higher?
The only other thing I can think of is that the change out of the pumps caused the problem. While there is clearly water circulation with the Koralias, they don't break the surface like the penguin. Does this mean that there is not enough air exchange (esp. since this is a hex tank).
Is the live rock in danger of dying off? (Much more costly to relpace than the fish...).