my fish died :(

Question
Last week I bought a new biorb tank - 30 litres - and two baby fantails. I researched thoroughly how many fish the tank could hold, followed all advice like letting the water sit for 24 hours and adding water conditioner, bacterial starter that came with the tank, etc. i also got a  generic tank weed plant. My fish seemed fine and lively for the first few days but on monday one of them was dead when I got in from work and the other was swimming funny. I looked online and suspected swimbladder disease so I stopped feeding unless he was constipated but he became gradually more inactive, just lying at the bottom of the tank and today when I came home he was dead. I did everything right according to all the advice I have seen although I did give them some cucumber as a fresh food treat - could this have killed them? Before I get some more fish should I throw out all the water and start with fresh, should i throw the plant away or wash it and is there any other advice you could think of? thanks, kat x

Answer
Hi Kat;

I retrieved your question from the "question pool" so I could help you know more about what's happened. I'm so sorry you lost your little fantails. What happened was the result of "New Tank Syndrome". Waste toxins built up in there because it didn't yet have adequate colonies of beneficial bacteria to consume the waste they were making. Here is a link to my article about new tanks that explains the whole crazy process;

http://www.xanga.com/Expert_Fish_Help

The trouble with fantails and other goldfish is that they are very messy fish that need lots of space. Each one needs 40 liters of water per fish as they grow. This unfortunately means that the biorb you have isn't big enough even for one fantail. The biorb, in spite of it's advertising, doesn't have adequate enough filtration or surface area for goldfish to stay healthy in. Here is a link to more information on goldfish and what they need;

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

You might consider getting some guppies, or zebra danios, or white cloud mountain minnows for your biorb. They are okay in small spaces like that. Even a male betta and some cory cats would do well, as long as the room temperature is warm enough. The others I mentioned are cold water but bettas and cories are tropicals.

At Your Service;
Chris Robbins