I have 5 young (2") synodontis in a 40gal L. One guppy is gone and one has had his tail bitten off. It happened at night. My Synos are nocturnal. Little Stubby (new name) is fine and now in hospital tank. I'm now feeding catfish before going to bed. Mollies, Kitty Tetras, a Betta and Dwarf Gourami are ok so far. I'm watching them. All I can do now is move fish to another tank if there's a problem and put larger tougher and faster fish in tank with catfish. Do you agree?