Re: Fish for a 5 gallon tank? I have a 2.5 gallon tank. I have 1 male betta in there. Could I add a female or I shouldnt because its a small tank? I keep having this damn brown algae growning in there too. I already took out the fake plant because it was covered in it. the tank has a 15 watt incandecent. its not on a timer but i turn it on when i get up and shut it off when i go to bed |