TigerBarb27

Hi,you know that nitrogen cycle thing where you have to wait a couple of weeks till you can put the fish in the tank?Well I just learned that and before I knew about it I just added the fish(mostly tiger barbs,1 pleco,and 1 rainbow shark)the night I set up the tank and they lived for months just fine in the tank,but the tanks I had before were small tanks(2-5 gallons)and im going to be getting a 30 gallon tank and Im worried they will die if I add the fish the night I put the tank up(cause it's bigger)but it's never happend before,anyone know why?

COBettaCouple

well, our first tank we didn't know about the nitrogen cycle and were lucky to not lose any fish. it just happens that way sometimes. The risk of death or illness is higher in an uncycled tank and the fish tend to live shorter to a degree, but there's always exceptions and many factors so it's best to cycle, but fish can be added to an uncycled tank, it's just a lot better for them to not go thru the spikes.

Gozer_1

The spikes in water quality get bigger with a higher bioload. If you only had a couple fish in each 5 then the fish probably only suffered some. The effect being most likely a shortened life span. The higher the bioload, the higher the toxins. The higher the toxins, the higher chance of death. It's in the best intrest of your fish to wait at least 24 hours. The longer the better. Think of it like this, the fish will likely live through the change but, you would still be killing them in the long run by shortening their lives. If you have the 5s setup now then leave the fish there for a while (another day or 2 won't hurt), run the new tank with an old filter pad in the new filter or a piece of any bio filter media you have from your existing tanks. You can add various Biological Boosters to help. I use StressZyme.