Hello. This morning, I counted my 9 neon tetras and I only found 8. I looked inside the filter, took the sponges out and nothing was there. I put the sponges back in and a dead neon tetra was floating in the filter. We were sad because he was smallest one and my sister's favourite and now I want to prevent any more fish from being sucked up in the filter and dying. This is the tank/filter I have: How do I prevent small fish from being sucked up in this type of filter? Thank you.