45-gallon long and a species of bichir. They are Jurassic fishes with arm-like pectoral fins and primitive lungs. They can literally survive out of water, pulling themselves along on their arm fins or wagging their tail to move forward!!
They are very hardy and adaptable, thriving in various water temps and conditions, which makes them an easy beginner's predator. They have very thick and uniquely shaped scales, so it makes them pretty impervious to common tropical diseases and parasites. They also eat anything from live fish, bugs, and live shrimp to tidbits of thawed steamed cocktail shrimp and raw fish/beef heart to bottom feeder pellets, cichlid pellets, and catfish bait... so they're easy to find food for!!
I love mine. I bought her when she was only 3 inches or so. I've had her almost a year now and she's twice that size. They get to be something like 12-16 inches in captivity and they're just plain neat to look at and have amazing personalities. They do fine kept as a single fish, or you can keep them with others as long as those fish aren't small enough to fit in the Bichir's mouth... but don't ever let it get hungry!! You'll have fish with bites out of them!!!
So there you go. It's a fantastic conversation fish, considering it's unique look. It's very personable, very adaptable, very hardy, fairly resistent to parasites and such, and it's easy to feed and maintain. The only drawback is the amount of space they need... but a 40 gallon would work for at least a couple of years before you'd need to upgrade.
Here's some images of different Bichirs. Enjoy!!
Nifty Photos and A Video Clip: http://images.google.com/imgres?img...ev=/images?q=bichir&gbv=2&svnum=10&hl=en&sa=G
Keeping Bichirs:http://www.thetropicaltank.co.uk/keeping_polypterus.htm
Once you figure out a type you like and that'd suit your space requirements, google it and you'll find tons of pictures and information.