fresh water fish tank your thoughts ?

[renovation]

me and the wife are thinking of getting like a 15 or 20 gallon tank. its been a long time from are last one we had.
the tank we had last time had what I think is called a under gravel filter .were it filters the water by pulling it though the gravel on the bottom of the tank. also what types of fish im sure we will buy at least one red tail shark i always like them. we will spend around $75 - $100 on the tank and fish . what you think are tank may get stocked with (types of fish)

[DarkFury]

Well if the choice is only between a 15 and a 20... I'd go with the 20.

Ditch the undergravel filter... nobody really uses those anymore and get yourself a "hang on the back" power filter (and maybe an air driven sponge filter).

As for fish... a 20 gallon can't support too many fish so if you just stick to the basics (tetras, barbs, danios, etc...) you should be fine. I wouldn't go into any "medium" sized fish (like Angelfish) as they'll outgrow that tank in a hurry.

BTW... red tail sharks are VERY aggressive. So if you get one, be sure not to buy any "timid" slow moving fish as they'll just get chewed up.