Expert: Chris Robbins - 7/14/2009

Question
Hi Stacey
I have a 29gal. aquarium. I started with 10 goldfish but now i am down to 7. I assume the first one died from the water heater, so I turned it off. The second one stayed at the top of the tank in the corner and died the next day. And with the third one i saw a struggle. He would try to get to the top gulping but would sink back down on his side as he continued to do until I flushed him. The tank was level full with one filter but i emptied it halfway. What should I do to prevent the others from dying?

Answer
Hi Janita;

Ten goldfish is just way too much for a 29 gallon tank. Waste toxin levels have probably gone too high and are poisoning them. As time goes by the weaker ones succumb to the stress. Those guys are messy and need at least 10 gallons per fish as they grow to maturity of about 8 inches.

All tanks need a 25% water change once a week every week to keep the fish healthy. Change the water more often if the tank is overcrowded, just like yours is now. You can change 25% of the tank water two or three times a week to keep them in better shape until you can get a larger tank or until you can re-home the extra fish. It is important to make smaller changes (25%) more often and not to change a large amount less often. Here is more info on goldfish and what they need to thrive;

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

Please don't "flush" fish until they have actually died. It's a long agonizing and suffocating death for them. Here is a web page about how to euthanize fish in a humane way if you need to do that again in the future;

http://thegab.org/Articles/Euthanasia.html

At Your Service;
Chris Robbins