Our 110 gallon indoor goldfish pond, situated against a load-bearing wall in our dining room, was built with a 2" x 4" frame, sided inside, outside and on the bottom with 1/2" plywood.  It was then tiled and grouted.  The inside was lined with outdoor pond liner and was stapled to the plywood.  Silicone was applied over the staples to keep the structure waterproof.

Pond Filtration

Filtration was a Laguna PowerFlowMax 1000 Biological Underwater Filter filled with foam.  The pump for the filtration system was placed at one end of the pond, while the filtration system was at the other end.  The two were connected by a long 1" diameter hose.  The outlet of the pump was moveable, and we pointed it upward and toward side opposite the air pump.  This set up provided maximum water flow and maximum water movement at the surface providing excellent gas exchange.

Goldfish are sensitive to ammonia and nitrite, both of which are natural by-products of fish waste that are present in an environment where there are insufficient bacteria present to consume these toxins.  Therefore, care must be taken to make sure the pond has a chance to build up these beneficial bacteria through a process called cycling.

The cycling process can be started by adding household ammonia (without additives) or by adding fish food to the pond.  Cycling can take as long as 6 to 12 weeks, so patience is required to establish a healthy environment for all goldfish. 

Testing the pond water periodically for ammonia and nitrite and recording date and test results will help determine where the pond is in the cycling process.  When both ammonia and nitrite levels are at 0 ppm and nitrate levels are noticeable, the pond is cycled and goldfish can be added one or two at a time, depending on size.

Pond Care and Cleaning

About 25 gallons of water weekly were siphoned from the pond bottom to remove leftover food and fish wastes.  Doing so kept nitrate levels down to less than 10 ppm.  Foams were thoroughly cleaned weekly in outgoing change water. 

We used tap water for the pond, dechlorinated with Prime, which was stored and aerated in a new 25 gallon Rubbermaid garbage can for several days prior to use.  Long term aeration was done to make sure new water going into the tank was sufficiently oxygenated.

At first, we had 2" of rock substrate and several silk plants, but it proved too difficult to keep pristine clean.  Eventually, we removed all the substrate and replaced it with a couple of bags of polished river rock from the craft store and baseball to football sized unpolished river rock. 

Goldfish are temperate water fish and typically do not require heating.  Water temperature in our pond was that of the house, ranging from about 19° C in winter to 28° C during the hot days of summer.

The dining room in which the pond and goldfish dwelt.

Our house in winter, the real reason we needed
the distraction of an indoor goldfish pond.

We fed beloved goldfish twice daily, either with flake food or a frozen homemade concoction.

Food was added to the pond where the current wasn't too strong, so the fish could have a easier chance of catching the food.  Food that was not eaten within three minutes was scooped out with a fish net and the net was rinsed thoroughly in tap water then let dry.

We were lucky not to experience any health problems with our goldfish.  For excellent information on disease and treatment, visit the Puregold website.