posted 02-13-2004 06:56 PM         

That rule only applies to slender bodied fish such as barbs, danios, and tetras. And you have to take into consideration the adult size of that fish. So for example, sure you could probably fit 100 1" tiger barbs in the tank right now, but by the time they reach their adult size of 2", your tank will be overstocked. So when you're figuring the stocking level, you will have to use the adult size of the fish.

Also, IMO, there really isn't any set rule that applies to all the larger fish. I think the best thing to do is do a search for the fish you are considering and check out the minimum tank size recommended on several sites. Then you can pretty much figure the average. For example, if you did a search for the minimum tank size for oscars, you would probably come up with maybe 1 site that recommends 30 gallons, 8 sites that say 55 gallons, and one site that says 125 gallons. So it's pretty much safe to say 55 gallons is the bare minimum for one oscar (although the one oscar in a 125 gallon tank would be a VERY happy fish ).

posted 02-13-2004 07:04 PM         

1) Aggressiveness - some fish can only be kept by themselves. Others are fine with different species but will try to kill other's of their own species (red-tailed sharks and rainbow sharks are good examples).

2) Social behavior - some fish do best in groups so if you have just one, it will be miserable (most barbs, tetras, danios, cory cats and some other fish).

3) Size of the fish and dimensions of the tank. This is actally why a lot of people question the 55 gallon minimum for oscars. An oscar can get over 14" long (standard length - not including the tail). A standard 55 gallon tank is only 12" wide so the oscar may have trouble turning around or at the very least, there's only 2 directions he can face.

I'm sure all of these won't be applying to fishyfriend4u, but in general, they are good things to keep in mind when figuring out how to stock a tank.