Where are my fishing?

Question
QUESTION: I have a 55 gal freshwater tank. Recently I added a couple of powder blue gouramis and some swordtails/platties for color, 2 angles for a different shape and two rainbows which are one of my favorite fish.  I already had several danios, a pleco and Mr. Kitty, my long time catfish who is about 6 inches long now. Several of my new fish disappeared with 2 days of being put into the tank; there is no evidence they were ever there!  I tested the water using a 5-n-1 test strip and the numbers are perfect conditions according to the testchart.I do a 50% water change every 2 weeks and I test the water often. Temp of tank is about 70 degrees.  So where did my fish go??

ANSWER: Debbey,
warm up the tank to 75-78 if you can..
What kind of catfish is Mr Kitty>?
He could be enjoying the missing citizens.


---------- FOLLOW-UP ----------

QUESTION: I keep the temps low because I read somewhere that by doing so, it helps keep the nitrates in check.  Is that not true? I can certainly raise it.  Should I raise it slowly over time?    

I believe Mr. Kitty is a common channel cat.  He swears he didnt even know there were other fish in the tank.  I thought catfish only ate dead stuff?  Another untruth?

Answer
deb,
keeping the temp low has nothing to do with the nitrates. Raise it.
Second, Mr.K is a mouth with a tail that is where your fish are dissappearing.
Also, MrK will get giant after a while the only safe fish are ones that he cannot eat, they have to be larger than his mouth...