Expert: Darryl Miller - 4/1/2007

Question
I'm planning to put goldfish in a 10 gallon tank at my workplace.  The tank
was set-up today, will run for about a week before any fish are added, and
hardness/PH should resolve themselves in about 24 hrs., based upon the 20
gallon I set-up yesterday at home.  

Do you have any suggestions concerning the number of goldfish that can live
in the 10 gallon tank and the number of catfish required to support them?   

It has been 20+ years since anyone in my family has cared for goldfish.  
Last
time, my goldfish lived in his own 10 gallon tank with one cat; hardiest fish
I've encountered, he survived 2 months in a cooler during a move/unplanned
stay at a hotel.

Thanks for any advice  

Answer
Hey Felicia,

Really, a single adult gold fish will be 14" long, if raised in ideal conditions. Because goldfish are coldwater fish, no tank cleaner really will mix well with a goldfish setup. If you're looking for a low cost, pretty, and entertaining community tank that's super easy to care for, consider a mix of 6 neon tetra, 3-4 zebra danios, a chinese algae eater, and a pair of african dwarf frogs. Add them to the tank 3 animals every 2 weeks until your tank feels full. (probably 6 neons, 3 danios, 1 chinese algae eater, 1 frog, and a plant)

If you're set on goldfish, get a good filter. Good filtration can make or break a tank of any type. If you keep your tank in good working order, and you keep the water quality at it's best (especially during set up) your fish will live long, happy lives. With goldfish specifically, I would not keep more then 3 in the tank, and add a live plant or two. The live plants will suck up the nutrients needed for algae growth. Turning the lights off over night will also help control plant growth, as well as reduce fish stress and fish deaths.

Goldfish are cold water fish, needing an average of 65*F daytime high / low. If your tank set up without a heater runs higher then 70*F do not stock gold fish. Warm, tropical water will shorten their lifespan to about 1/10 that of ideal quality tanks. If you need an algae eater, a plecostomus is probably not a good choice. They can grow upto 20 inches in my experiance, and weigh in just over 4 pounds. That's about half the size of the 10 gallon tank. So long as you do not over feed your fish, and you have a small to medium sized gravel, the gold fish will pick up the gravel and rotate it daily. This rotation prevents algae growth along the bottom.


Honestly, goldfish are easily kept, and will do well for a year or two in a small tank, however once they grow to about 4 inches each, they really need around 30 gallons (for another year or two, until they're around 6 inches, then they need 70... and so on until they're 12 inches, in a 125 gallon tank).


If you don't wish to keep moving your fish to larger tanks as they grow, guppies, neon tetra, danio, frogs, and other small tropicals will happily live in a smaller tank (so long as you do not over fill the tank too quickly). The color, playful swimming, and surprisingly easy care would prove a community tank just as fun and effective as a goldfish tank, in a much smaller space!

Best of luck, and hope this all helps.