I had the same situation, My puffer was larger than the trigger. The puffer was in the display tank first. I had the trigger and a Maculosous angel in QT together. Once I put them in with the puffer, believe it or not, my damsel went after the angel. The puffer didnt bother anyone. Once I removed the damsel, the angel went after the puffer. Now, though, the puffer, trigger and angel have been living happy together. I agree, keep the trigger on the small side