So I bought 10 neon tetra for my 3 week old 30 gal tank...it was cycled and ready to go..I acclimated and made sure all 10 were good and then went upstairs for a nap. I woke up and there were 9....i searched everywhere and couldnt find it. My BF then convinced me that i couldnt count and i only got 9... 2 days later i came home and the missing fish was in the filter intake tube!!! I SWEAR IT WASNT THERE BEFORE! now that i got it cleaned up the tank has a slight odor and amonnia was at 0 is now at like .25. What should I do?