Guppies are so small that it is entirely likely they will get eaten, sooner or later.
I lost a school of Neon Tetras to some Yoyos. The Yoyos must have grown 2" on the high protien diet! They were not much over 3" when they started 'fishing' for their own meals, and were over 5" when I removed them from that tank.
Probably Zebra Loaches (striatas) are safe. I kept them with Endlers Livebearers. They may have eaten some fry, but the adults were safe.
I would not trust any mix of fish where the larger is twice the size of the smaller. (Though the striata + Endler mix worked). And the Clown Loach: Guppy ratio is more like 3:1 when you start, and gets worse.
26 tanks, over 3000 liters of water to keep clean and fresh.
Happy fish keeping!