Wow, I’ve never seen big Amanos show up there.
As for shrimp and fish getting in the filter, are they getting past the prefilter? If so, it could definitely be them coming in through the outflow. I’ve had fish swim into the mouth of a lily pipe before, but none ever make it very far—usually the flow pushes them right back out. Oase filters have extremely low flow (often around half of the listed rating, and the listed rating already feels low), so I guess it’s possible.
When it comes to larger filters I am firmly on team Aquael after trying most of the major brands. The flow is easily double the equivalent Oase, they’re cheaper, and they’re consistently quiet. My Biomaster Thermo 2 250 has been a nightmare—it stays loud even after a fresh impeller clean and after shaking out every bit of air. The flow is about enough for the 60U and no more.
As for CMAC, I’ve had about 50/50 luck with them. My best pickups from there were my Keyholes and Von Rio tetras. The Von Rios were in a back tank for over a month, so they were essentially quarantined before I bought them. But most of the time they turn over fish so quickly that it’s a gamble whether you get healthy ones. Unfortunately, I’ve lost 3 out of 4 SAEs and 2 out of 4 Panda Garras I bought from them. They were probably already weak, and I should have moved them into a dedicated tank to baby them early on.