If you look on the Reefkeepers mailing list you will find a thread about a pod identification, started by Mindrasr, and answered by Dr. Ron. The pod in question was identified as a predator of fish, and kinda resembles what you described. There is a pic, if I can find it I'll post it.
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Bill Esposito
bespo@cereal.mv.com
JAqua for the AquaController 2
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