There are a couple different fish called a whiptail cat--some are really long and thin, also called a royal farlowella. The other is in the loriicaid family, shaped like a sturgeon, with little, feathery like spikes on the fins, and a long thread-like piece coming off the top of the tail fin. I have three of these. They are about 6-7 inches long (not included the 'whip') and are very peacefull. They eat just about anything, but seem to prefer a bit of meatiness to their diet. They need caves or overhangs to hide out in, and will bury themselves if provided with sand or very small, smooth gravel. Neat fish--I'm hoping mine will breed.