Sucked into Filter?

Question
I'm a brand new aquarium owner (never had one before.)  I really enjoyed the look of the Biorb 8 Gallon freshwater spherical tank.  We cycled the tank without fish and then added 3 Zebra Danios after about 2 weeks.  Everything seemed to be going okay for a couple days.  Then, we only had two fish in the tank.  We couldn't find the other one!  Then we started getting a white slime on the bottom.  I cleaned all that out, and did not find the body of the first fish.  About another week went by, and then I only had one Danio left.  So, yesterday we cleaned the entire tank out including the filter.  Well, the two poor little danio bodies were stuck inside the filter in between the top of the plastic casing and the sponge filter.  I'm wondering how they got in there?  And did they die first %26 then get sucked in or is this particular tank too strong for such small fish? We want to be responsible fish owners and not overcrowd (which is why we got such small fish.)  Now, I only have one danio left and he seems to be doing okay (maybe lonely?)  So, what can I do to ensure the safety of my fish from being murdered by the filter?  And would it be a safer to get slightly bigger fish?  Should I add another layer of rock on the bottom in case they got into the filter from the bottom?  Thanks for your help!

Answer
Hi Tessa,
 In almost all cases, the fish dies (or gets very weak) and then gets pulled into the filter. In other words, the filter is not the problem.  The white slime is a very bad sign.  Are you overfeeding your fish?  Many new fish keepers vastly overfeed their fish.  A fish has a tiny, tiny stomach. I recommend only feeding them once a day and only food that they eat right away.  Never put in food for them to "eat later".  Rotting food could easily be the cause of both the dead fish and the white slime.  

-- Ron C.
  rcoleman@cichlidresearch.com
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