Originally Posted by YoAlyssa
I lost every fish in the tank.
What should I do now? I would HATE to have to break down the entire tank and kill off all my beneficial bacteria.
I would were it me,, remove the filter material from the tank and toss it away. I would then gravel vaccum the tank until water level was down to where only the gravel was covered with water. I would remove all of the decoration in the tank and scrub them with bleach and water solution. I would also scrub filter parts,hoses,etc. Then I would load the filter with all new filter media including activated carbon and refill the tank. I would let the tank run for at least ten days with no fish . I would also at this time place decorations back into the tank. You will in effect be starting with a new tank, but some filter material from your other tank, or tanks, will serve as seed material for your now Cycling tank and make it safe to add three or four SMALL fish (ie) silvertipped tetras,bloodfin tetras,or pristilla tetras. These three or four small fish will not create a large bioload and will serve to help establish the bacteria in the tank along with the used filter material from your other tank which you will have added to the filter on the cycling tank. I would let the tank run for ten days with these SMALL active fish and observe for any signs of distress while feeding them sparingly. With the seed material you used from your other tank ,there should be no dangerous levels of ammonia or nitrites assuming you don't overfeed the fish. At this time,if all fish appear well. I would resume weekly 25 percent water changes and continue to stock the tank slowly.
I would also use a dechlorinator such as PRIME or AMQUEL+ for all water changes from this point on.
Some would say that adding the seed material from your other tank to the one you drained will make it possible to add fish immediately, and normally,, I would agree. However, I am also considering that some type of pathogen may have been responsible for sudden deaths you experienced, and by letting the tank run for ten days to two weeks,, many pathogens will not be able to survive with no fish to serve as hosts. Is why were it me,I would not add fish for the period mentioned. The filter material borrowed from your quarantine tank should allow you to mature or (cycle) the tank once again in a matter of days if done as described. Good luck!