Don't get discouaraged. It could be possible that when your first livestock died, whatever killed it is still in the tank and carries on to everything else you add. Wait a while, maybe a month or so and just keep doing water changes.
I believe I saw your parameters in a different post and heard they were good. What type of equipment are you running, what is your set-up like, what did you fill your tank with? This may be a little random, but what did you fill the enitre tank with in the beginning? Water typse wise.
However just wait a little while and keep doing some water changes. If nothing is in your tank right now as far as fish and corasl go, plan right now what you want to keep in the future. |