Planted Tank Setup - basics

Question
I have an old aquarium 20*12*15 with plastic plants, i wanted to move for a more realistic and bigger tank so i went to my pet shop and discussed for a tank with live plants, he has suggested me a 36*12*15 with open top,and he assures there will not be a need for co2 process. He has added a Top filter, 20kgs of sand and 8kgs of fertilizer.As for the plants since he had to bring it from the nursery i wasnt able to choose yet. I have already placed my oredr and getting my tank set up this weekend. As for fishes i currently have 4pairs of zebra danios, 1pair redy eye tetra,3 firetail guppies and 1pair of red molly. Please let me know if i can have any changes to the size of my tank, do i need a co2 process or can i do without it? will my fishes jump in a open tank? I plan to add tetras, how many can my tank accomodate after decorating my tank. what fishes can be added to the exsisting community? Since i have had mollies jump in my bowl should i remove it?  

Answer
Hi Karthik;

I'm not a plant expert and am not familiar with CO2 systems so I really can't say if it's needed or not. I didn't see any mention of lighting in your setup though. Is there a reliable source to keep the plants healthy? Most live plants need some seriously bright artificial lighting when kept indoors.

All tanks really should have lids. Your fish can jump out, dust and other things can fall in, and the water will evaporate at an incredible rate because of the filter circulating and the tropical temperatures. You will have to add water almost daily to keep the water level consistent. If you have other pets such as birds, dogs and cats they can be a threat to the fish as well. They will drink the water, try to catch the fish or even fall in. This can introduce toxic chemicals from flea and tick remedies, or anything else you use on your pets, into the water. Birds can even drown in an aquarium.

You will want to know about "New Tank Syndrome" or the break-in period too. You can't safely add all those fish all at once. It will add too many waste toxins too quickly. You will want to add only one inch of fish for every ten gallons until it is fully through the break-in period. Here is a link to my article about it;

http://www.xanga.com/Expert_Fish_Help

After the initial break-in period that takes about 6 weeks, add one inch of fish for every ten gallons again. Give the tank a week to compensate for the new population and keep doing that until you have the population limit you want. Your tank is about 35 gallons so the maximum population you will want in there is about 35 inches. You will want to know the future adult size of each fish so you can calculate accurately. I really think the fish you have now is plenty, but look into their future sizes to be sure. Go to this site or any other with fish profiles to know about each one;

http://www.fishprofiles.com/

Here are some web pages about stocking your tank and future fish sizes as well;

http://www.firsttankguide.net/capacity.php

http://freshaquarium.about.com/cs/beginnerinfo/a/fishcalc.htm

http://www.firsttankguide.net/size.php

Have fun!

At Your Service;
Chris Robbins