These might be some dum questions

[jesseh83]

I have a 55 gallon long tank that I am going to make it into sw. I have heard that you dont need a skimmer and sump from some people and from others I have. I would like to save as much money as possible but I dont want to kill my fish or stress them out. I plan on having a fish only tank because my wife is set on having a puffer fish, but I might put a little bit of live rock or coral in the tank.
I guess what I am asking is
Do i need a skimmer and why
Do i need a sump and why
What is the difference between live rock and coral

 

[btldreef]

A skimmer and sump are not absolutely necessary, but they do help. Puffers, and most "fish only" fish can be sloppy eaters so having the extra water volume of the sump and the skimmer sucking out extra waste can be very helpful. With proper maintenance, neither are absolutely necessary, but nice safe guards.
Live rock is rock. It can, and usually is, made up of dead coral skeletons. They serve as natural filtration. Corals, well they're still alive. That's the simplest way of explaining it.

 

[jesseh83]

Thank you for explaining it. I understand it better now. If I go with just a skimmer and keep up on my water changes would i be fine?

 

[btldreef]

If you keep up on water changes and maintain good habits, you don't even necessarily need the skimmer. Sumps and skimmers are also something that can be added on over time. Of the two, I'd go with a sump before a skimmer to increase water volume. This way, if you decide to go with a skimmer down the road, you can get a better one. In sump skimmers are almost always better than hang on models, at least that has been my experience.