sad /crazy goldfish

Question
hey there
just wondering can you help.
my cousin has a fairly big tank and only one goldfish (the other three died ages ago) and shes had it about2 years maybe. i decided to buy another goldfish for the tank and bougth new stones. i put hte new fish in and not exactly properly somaybe thats what affectedit but they'e both actuaong strangely, she cleaned the tank and changed the water the same day i think.
the both either lie at the bottom of tha tank and barely move or respond where you're near the tank or else the swim really fastley around and what into the glass, i can't understand it,
any ideas?
we have no filter either.

Answer
Hi Siobhan;

Poor guys. Waste toxins are irritating and burning their skin, gills and eyes. It's like poison to them so their nervous systems are a bit out of whack. Change their water again and do it every couple of days. Get a filter on the tank to help remove some of the waste. It may be that the tank was just large enough to keep the one fish alive without filtration but not for two. That's double the waste being put into the system. Goldfish are very messy fish that put out more waste than other fish. They really need good filtration as well as a tank size of at least 10 gallons of water per fish in order to thrive.

Here is a good page about goldfish to help you know what goldfish need so you can provide it for both those guys;

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

I hope they feel better soon...

At Your Service;
Chris Robbins