Most disasters with goldfish start the moment they are purchased. If you think you can purchase a goldfish, throw it into a new aquarium or pond, and expect it to thrive, you are sadly mistaken, or very lucky. Most of the basics such as setting up the aquarium and quarantine tank should have been done prior to the purchase of your new pet.

1. Pre-purchase Checks

Before you hand over any money for your goldfish ensure the specimen is healthy. Stand back from the aquarium the goldfish is in and observe the following;

- Is the fish active and looking for food? It shouldn’t be sitting on the bottom.
- Are all the fins present, un-frayed at the edges and being held erect and away from the body?
- Are there any red patches on the fins or body? (Hard to see on red or orange coloured fish).
- Is there any white cotton wool like patches or pinhead size white spots anywhere on the fish?
- Is the body full and rounded? (Consider the goldfish type you are purchasing. A healthy Comet will be a lot slimmer than a sick Fantail, but the body should still be rounded and smooth, not appearing wasted).
- Is the goldfish breathing normally, not fast compared to other fish in the aquarium?
- Does the fish’s movement appear effortless or is it laboured as if it is struggling to keep buoyant?
- Few if any scales should be missing, and they shouldn’t be extended like a pine cone (unless the goldfish is a Pearl Scale).
- Is the fish twitching or scratching against the gravel or aquarium sides?

2. Compatibility With Each Other

All goldfish are not created equal. Don’t mix goldfish with large differences in size or traits. By this I mean if you mix a Black Moor goldfish that has two tail fins a bulbous body and poor eyesight with Comet goldfish that have a single tail, slim body and good eyesight, it will starve.

3. Getting Your Goldfish Home Safely

Your goal here is to maintain the temperature of the water your goldfish is in now. Goldfish are poikilothermic. That means they are at the temperature of the water they are in. Unless the journey home is a short one, the plastic bag should be put into a container with thermal insulation properties, (Eskey, chilly bin or something similar). If the car has air conditioning, even better. Sudden changes in water temperature will stress the goldfish leading to death or disease.

4. Introducing Your Goldfish To Its New Home

There are three important water conditions that need to be checked before putting your goldfish into its new home.

- Water chemicals
- Water temperatures
- Water pH

Water straight from the tap contains chlorine or Chloramine. This can kill goldfish if it is not removed with a water conditioner such as Stress Coat, or left to gas off overnight with the aquarium filter running.

There will probably be a temperature difference between the water the goldfish is in, and where it is to live. There will almost certainly be a difference in pH, which I call the invisible killer. More new arrivals are killed by pH differences than everything else added together.

Never use pure rain water, the lack of chemicals means it cannot support life.

This is the correct method to introduce new arrivals. Float the plastic bag in the aquarium. If the plastic bag had pure oxygen added, leave the bag closed. If not, open the bag. Be aware that some single tailed goldfish like to jump in stressful situations. Watch for any signs of stress such as gasping at the surface. After an hour, or when the temperatures are the same, slowly start mixing the water in their bag with the aquarium water over an hour or so to equalise the pH. Only after you have equalised the pH, gently tilt the plastic bag and let the fish swim into the aquarium.

5. Always Quarantine New Arrivals

Most goldfish have been raised in large outdoor ponds with plenty of room. They are then caught, shoved into small crowded tanks with less than ideal water quality. Assume your new arrival has caught some disease due to stress, or is a carrier of disease. Your new arrival should be quarantined in a separate container with a small amount of medication added for two weeks before it can be considered clear of disease. Plain un-iodised cooking salt is good for this at 1-2 teaspoons per gallon. Goldfish are very tolerant of salt in their water.

6. Aquarium Ornaments Can Be Dangerous

Some rocks, driftwood and sea shells dissolve in aquariums affecting the pH and staining the water. Ornaments shouldn’t have sharp points or edges if fancy goldfish are going to be kept. This is especially important if the fancy goldfish have poor eyesight such as Moors, Water Bubble-eyes and Celestials. Gravel needs to be cleaned regularly using a gravel cleaner to avoid a build up of wastes.

7. Aquarium Tools

I am assuming you have an aquarium of the correct size with a cover. There is a minimum amount of basic equipment needed to maintain an aquarium. These are indispensable items;

- Net. Get one with the most open weave you can
- Thermometer to check water temperatures when moving fish around
- Water test kits for measuring pH and ammonia levels
- Siphon hose for water changes and gravel cleaning
- Quarantine tank/container for when a fish becomes sick.

8. Aquarium Maintenance

There is only one thing you need to do regularly that will make you appear an expert in goldfish keeping. Change 50% of the water regularly. Changing the water regularly does several things, it regulates pH, (remember the invisible killer), and it removes nutrients so algae growth is controlled. I’ve seen overfed, cramped goldfish thriving because the owner made frequent water changes. Your test kits will tell you how often it is needed. Just because the water is clear doesn’t mean the pH and nutrient levels are satisfactory.

9. Sickness

Even experts make mistakes. If your goldfish gets sick, most complaints resulting from poor water conditions can be easily cured. Remove sick fish from the main aquarium into the quarantine tank that has had salt added to the water. Introduce the fish to the tank in the same way as you would a new arrival.

10. Feeding

Goldfish are omnivorous meaning they eat plant matter and meat. Don’t expect your goldfish to thrive on that dried up old time expired packet of fish food. Give them some live food regularly, once a week at least. If you can’t or don’t want to raise mosquito larvae in the back yard, frozen foods are available from your better pet shops.