Today I walked upstairs and heard a buzzing noise coming from my cichlid tank. I looked to see what the noise was. Low and behold I see one of my holding female zebra obliq's head sucked into the bottom of my powerhead. I thought she was done for. Then I shut off the power head and saw her wiggle so I grabbed here by the tail and pulled her free. Her face has a little damage. I think all her eggs are ok. It looks to me like the powerhead sucked blood into her face, because it's all red. Hopefully she's ok, needless to say I put the filter back on the power head.