So sorry you lost your blenny, especially in that way. Just thought I would mention my experience with this. My tail spot blenny loves to swim inside the propeller cover for my Tunze Stream 3 powerhead when it is off, especially because it becomes a algae garden it cannot otherwise eat. However, the Stream 3 seems to have 2 features designed to prevent fish from getting blended in the propeller. First, in feed mode the propeller spins very very slowly, creating no flow but keeping inhabitants from going inside the cover. Second, when you do power it off completely and it comes back on, the propeller ramps up in speed slowly, with enough time for fish to get away. Not sure if these features were intended to keep fish safe, but in my observation they do. While the Stream 3 is not cheap, its been fantastic and given my positive experience with Tunze warranty service I'm confident that the 5 year warranty it comes with is worthwhile.