3 1/2 Week Cycled Tank, Fish Are Dying...

[aly2k9]

Thank you for everyones help. My filter is now working again. i will purchase a backup today along with the test kit. Is it advisable to redo the full tank. Give everything a clean inlcuding filter and start again.

 

[Tropical_Fish]

I think what everyone is saying is to read the beginners section. Read the Fishless Cycling and Fish-in Cycling methods.

You need to do one of those methods to grow the bacteria in your filter, you sort of did the fish-in method last time but didn't do any of the bits needed to keep the fish alive. The fish-in method is a lot more intense and requires daily water changes. The fishless method is loads easier, it just involves testing the water a lot and being patient. (you will have an empty tank for about a month if not longer)

I think you also need to read up on what fish are suitable - neons are likely to die even if you do everything correctly as your tank isn't mature enough to support them.

 

[OldMan47]

It is never a good idea to clean everything and start again when the original problem was failing to cycle the tank. That just would set you back to day 1 of a new cycle. At least where you are, the tank's filter will have made some progress toward cycling.

If there was a disease in the tank that had the fish showing some kind of symptoms, that might be a different matter entirely.

 

[flying_jack]

sounds like ammonia poisoning to me but im not 100% sure. Is the last tetra still alive?