what fish are suitable for a cold water biorb

Question
Hi, I'm thinking of buying a baby biorb 15 litre cold water aquarium as a gift, what fish are suitable and how many will it safely home? Also, I own a 30 litre cold water biorb, and currently have in it a pearlscale and a very small fancy goldfish and have recently purchased two canary goldfish.But, the canary goldfish, although much smaller than the pearlscale, are attacking it so i will have to remove the canary goldfish. are they suitable for the 15 litre baby biorb? When I have removed the canary goldfish from the 30 litre biorb what fish and how many would be suitable to join the pearlscale and the small fancy goldfish? Sorry about the number of questions, hope you can help, many thanks, Allison..

Answer
Hi Allison;

A little 15 liter cold water tank is large enough for perhaps 2 or 3 danios or 2 or 3 white cloud mountain minnows. The standard rule of thumb for small types of fish is 2.5 cm for every 4 liters if the tank has a good filter. Danios and white clouds get to be about 3 or 4 cm each.

You do have a serious problem looming with your current fish though. I know what the pictures on the boxes of biorbs show but they are not realistic and the company is lying to you about goldfish being able to live in any smaller than a 40 liter. I am so sorry you have been misled. Goldfish need at least 40 liters per fish to thrive (or ten gallons). So, unfortunately neither tank is big enough for even one goldfish to live in. They also have a very small surface area for oxygen/carbon dioxide exchange so you have to be careful that you stick with smaller types of fish. Goldfish are very messy guys that get very large, about 15 cm. Here is a web page about them to know more about their care;

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

Here also is my own web page about new tanks to help you get your tanks safely through the break-in period;

http://www.xanga.com/Expert_Fish_Help

At Your Service;
Chris Robbins