Originally Posted by Sumaii
I know this is a bit of an old thread but you REALLY need to get a bigger tank for those fish.
Gold fish usually need at least 15- 20 gallons a fish and an extremely good filtration system, which that tank is not providing.
Please upgrade them to a 50 gallon, they'll love you for it.
Your goldies are lovely.
The above poster is correct though, because of bio load that goldies produce, they need a minimum of a 20 gallon tank at the least (the bigger the better!) You can often find good deals on nice tanks on places like Craigslist.
If you upgrade them to a larger tank with a stronger filtration system you can also use a good bio-wheel to help out! I also suggest a heater (fancy goldfish prefer warmer waters). If you want a cleaner tank, you can add an appropriate algae eater as well. Contrary to popular belief, you CAN put a pleco in with them if you have a large enough tank and the pleco isn't small enough to fit into their mouths. I have a fancy goldfish tank with 4 goldies (2 ryukin, 1 red/white telescope, and 1 oranda). In that tank I also have a little high fin spotted pleco. (They're in a fairly large tank now, but if the pleco gets too large he will be upgraded into my 80 gallon.) Everyone gets along quite well. I've got all live plants in mine (the goldies love them!) and a large rustic ruines scene for them to hide in and establish territories.
You can not put a pleco in with comet goldfish/koi because they prefer cold water and plecos are typically tropical....however the fancy goldfish give you a little leway because they prefer warmer waters....so it works out
/ Not sure what you feed yours, but I thought I might mention what mine enjoy
They can have can have frozen blood worms, frozen peas, cucumber, live aquatic plants, frozen brine shrimp, sinking wafers, and flakes...(I do however avoid iceburg lettice and blackworms, and freeze-dried foods that can cause bloat).