fish care 101

I have a 2.5 gallon tank with a filter and would love to put a betta in. It held a mushroom coral and nearly a clown loach and comet goldfish. Thanks:-D Does not own any fish:(

I just bought my son a betta fish a few days ago, I bought a one gallon tank for him, despite the guy trying to sell me a tiny bowl. He's a veil tail, (the one in the picture is the guy who died the first day. He was a halfmoon I think.) he has two artificial plants and a fake submarine. I...

So I'm getting a heater for my tank and my tank is 40 liters I just wanted to know what size heater I should get and what not as I'm a little confused when it comes to stuff like that. Thanks again for your help :-D

First of all...Happy New Year! :) I hope everyone's off to a great start. Sorry for the long intro post, but I do have a little story to tell, if you don't mind. I'm really concern with my pet, and any help would be thankful. 8'D ((((((((((If you don't want to read, can you please look at the...