Selecting Fish:
Great, you've made it this far and it's finally time to go out and buy some fish from your neighborhood Fish Shop. The question is though.....

"What will I buy? What fish can live together? Which fish are mean? And which ones are friendly?"
Well there is no one answer for those questions. What I am laying out here is strictly a suggestive guideline. You can certainly ask you Fish Store professional, or consult a great book titled "Dr. Axlerod's Atlas of Freshwater Fishes". This book has some really great information. It may be a bit too costly for beginning aquarist's, but any decent Fish Shop should have a copy handy for you to look through.
whatever you do, ALWAYS research the fish you want to get BEFORE you get it, this can save you a lot of wasted time and money, not to mention the fish as well.

Well here are some different scenarios and my suggestions.....
( As always, get fish that are compatible with your water parameters, these suggestions will not work in all circumstances! )

"Hey Fish Dude, I just got my new 10 gallon tank all set up for my kids. What sort of fish would do well?"
Well, a couple of colorful Guppies, White Cloud Mountain Minnows or Neon Tetra's would do nicely, durable enough for the kids and not very expensive. Add an Oto-Cat in about three or four weeks. Then a week or two after that maybe add a pair Cories, or possibly even a couple of Kuhlii Loach.

"Hey Fish Dude, I just got a great 20 gallon tank set up in my office and would really like some unusual fish to show off to my clients. What would you suggest?"
A single Jurupari (or more commonly known as an "Earth Eater"). If you can find a Whiptail Catfish or Twig Catfish. The Whiptail is much more forgiving to beginners. A pair of very active Cory's and maybe 3 Marbled Hatchet Fish. Later on as the tank gets established add a Spot Finned Spiny Eel. Lots of color with this combo as well as top, middle and bottom feeders to help reduce the maintenance. If the tank is near a window or a lot of algae builds up, a pair of Oto-Cats would complete the tank.

"Hey Fish Dude, I just want some simple fish for a 20 gallon tank at home."
A couple of Angel Fish would look good, as long as it is a high tank and not the standard long version, or if it is a long tank, why not stick with some colorful Rasboras, White Cloud Mountain Minnows, a single Betta and a pair of Peppered Cories, simple pretty durable and rather inexpensive selections.

"Hey Fish Dude, I got this tall 30 gallon tank for the house. I want constant swimming with some really great color to show it off. Got any ideas?"
You can do a lot with that tank, but since it is a high tank vs. a long tank lets try a combination of these suggestions; 2-3 Angel Fish or Gouramies for the top and middle of the tank. 3-4 Marbled or Gold Hatchet fish for the top. A Jurupari for middle to bottom, or two yellow to red Cory's. Two Chinese Cats to complete the tank.

Some fishes that just do not play together well, First just the basics.
   Large fish and small fish don't generally mix well. The smaller fish tend to end up as dinner. There are of course exceptions to every rule, biggest thing is to research and check first!
   Cichlids are beautiful fish, however they tend to eat most everything else in the tank. If you like these guys, have a tank devoted just for them.
   Electric fish, such as the Black Ghost Knife Fish and Elephant nose's should never be mixed. In fact no more than any one of these per tank at a time. These fish give off small electrical currents. This is how they hunt for food. By having more than one, the electrical charges can interfere with one another, eventually ending in a slow death caused by starvation for most if not all of these breeds.
   Watch the sexes when you can. Too many males (and in some cases females) will end up in inner-tank fighting since the amount of territory is limited, especially with the colorful Bettas. No more than one male Betta (Also known as Siamese Fighting Fish) in a tank at a time.
   Generally with smaller fishes, they tend to do better in pairs or schools. For example; Hatchet Fish, tetras, rasboras, etc. do best in schools of 4 or more. Silver Sharks and many other catfish do better in pairs than they do solo ( but these are not small by any means ).
   If you can consult your Fish Store Professional, or better yet ask them to see the book "Dr. Axlerod's Atlas of Freshwater Fishes". Just about every fish store has this available. You can find invaluable information in there.
Okay first Timers, your just about done, one last click and its on to the fish!