Do you guys think that putting 2 <2"TL baby oscars in a 6'Lx20"Hx18"D tank would ever accumulate enough ammonia/nitrite to cause any problems before the bacteria would grow to manage the waste?

YES! An uncycled tank is an uncycled tank! It doesn't matter if it is 200 gallons or 20!

Besides without Ammonia, you will never get Nitrites, and in turn never get Nitrates...

So PLEASE PLEASE PLEASE cycle your tank BEFORE you get your Oscars!

Yeah I am going to cycle it first, I was just curious. I want big and healthy oscars, I am not going to risk preventing that for the sake of a few weeks. I am going to do a fishless cycle as well.

Good luck with your fishless cycle! I have cycled with danios and guppies in the past, and then left them in the tank for Oscar food, but if you feel the fishless cycle is right for you, then more power to you! Make sure to post pics when you get your baby(s)!

it is possible to cycle with your fish, with a large tank it becomes a little easier to manage.if your tank is 6ftx20"x18 and your filters correctly filled with bio media you should be able to cycle it with little ammonia/nitrite danger to the fish.assuming you only have 2 small(under 4" oscars) it would take regular testing and maybe water changes depending on the readings. if you feed correctly you may even manage to cycle the tank without any ammonia/nitrite spikes.

but unless you have good knowledge of maintaining water conditions I wouldn't bother and would go the other route. fish less cycle.

marcus wrote:


im with marcus on this one. In a large tank its possible but not recommended. You will still need to do regular water changes. Best bet is to cycle with fish you dont care about like goldfish or danios, just return them when you add your oscars (unless you want them to become oscar food)