betta tank - cycling question

Question
I have a five gallon betta tank, about 3 months old.  To my knowledge, it has never fully cycled.  Added a sponge filter about 2 months ago.  This week, I switched the sponge from a cycled tank with this one.  Ammonia levels were .25 on Thursday when I traded sponges.  This morning (Saturday), the ammonia level had dropped to almost nothing, but no nitrite or nitrate readings.  Is there a chance in a tank of this age and a cycled sponge that the tank will cycle gently and I will not get a significant nitrite spike?

I had an algae bloom start two weeks ago and it is going full bore at this time.  I would like to transfer two otos from another tank, but don't want them to experience the nitrites.  Would it be safe to put them in if I get another 0-0-0 reading?

Thanks for your help - mac  

Answer
Hello Mac!
If you transfered the sponge from the cycled tank quickly enough, then the bacteria probably stayed alive and immediately started to "eat" the ammonia. You may not even see a nitrite spike.
What I would do is a 50% water change to knock down the ammonia and put in your otos tomorrow if you see no ammonia or very little.
If after a day or two the ammonia or nitrite re-appears, the levels should be tolerable. I think you are probably cycled or real close to it.
happy Easter!