Fantail Goldfish in 10 Gallon Tank

[neoninnesi]

Firsty I know that a 10 Gallon tank is way too small for a fully grown Fantail. My question is, if I provided proper filtration (undergravel filter, cannister, and frequent pwc) how long could a Fantail (purchased around 1”) thrive in 10 gallons before the small size would stunt its growth? How quickly do they grow? For example, could I keep a Fantail in a 10 gallon for 6 months and then upgrade to a 20+ gal?
TIA

 

[Jessie J.]

I would say until it gets a month or so old, then move it to a larger tank. But if that's the only tank you have and you don't have the fish yet, don't get it.

 

[Jeremy180]

Depends a lot on his current size.
A good way to guess the size of a small round bodied fish to compare the body size to an egg.
A USDA graded small size egg averages about 42 grams,
Medium is about 50, Large is about 57, Very large is about 64 Grams and jumbo is around 71.
https://en.m.wikipedia.org/wiki/Chicken_egg_sizes

Personally I would give a small egg size fish of this shape no less than 8.5 gallons to itself, a medium 9.5, a Large 10.5, extra large 11.5, and no less than 12.5 gallons each for a jumbo egg size Fantail.

When you do upgrade, keep in mind that front to back width is more important than length to fancy goldfish, because while they can't swim very fast, they are also very bad at turning compared to other fish.

In the end, I would suggest nothing less than a 40 gallon breeder (36"X18" base) tank for one double tail by itself permanently , with a 75 (48"X18") being a much better choice for two at most with no other tank mates, as they can easily reach a body the size a nerf American football, and not uncommonly get significantly larger.
This is really the absolute minimum, and if you can go bigger than this, I certainly would, and not getting a tank any less than 16" front to back.

PS: IF his body is already bigger than an extra large egg, he needs an upgrade as soon as humanly possible.
Edit: As a note for anyone reading this in the future, shibunkin, comet, common, and other single tail goldfish are more active swimmers and really do better with at least a five foot tank, preferably 6 feet.

 

[Colin_T]

Most fantail goldfish are about 3 months old when you get them at 1 inch long (body size not including tail). If well fed and looked after, fantail goldfish can reach 4 inches long (body size not including tail) in 6 months. However, most people don't feed them that well so the fish will probably only get to half that size in 6 months.

Everyone is going to spit the dummy at me for saying this but you if you keep the water clean (do regular water changes and gravel & filter cleaning), you can keep 3 or 4 small goldfish (about 1 inch long) in a 10 gallon tank for 6-12 months. But you need to keep the water clean and they do better if kept in a bigger tank.

Once they are a couple of inches long you want to try and get them into a bigger tank or pond.

When you keep goldfish, only keep fantails together or single tailed fish together. Do not mix single tail with double tailed (fantail) fish because the single tailed fish swim faster, get more food, and male single tailed fish can harass females fantails when breeding.

 

[Jeremy180]

Just wanted to clarify, I agree with most of what Colin said, except in my humble opinion, he is greatly underestimating how fast four one inch Fancy Goldfish would outgrow that tank.
In my opinion, it would happen too fast for it to be practical.

 

[FishGuest5123]

Ok, just ask Goldie Mom here. I had 3 in a 10G for about 2 months then upgraded to a 29G. Rule of thumb is 20G for first and 10G for each additional. My fancies grew an additional 3-4” in a year. They were well fed. Now this is where I will get ridiculed but goldfish do not get stunted where their bodies stop growing but their organs continue. That’s crazy. If you keep your fancies in a 10G for say, 6 months, and then upgrade the tank to say a 40G, your fish will begin to grow again. Stunting doesn’t happen overnight or even over months. At least not permanent stunting. I had a comet in a 10G for about 3 months. Then moved him and a common into a 29G. They lived in there for about 4 months. They grew about 3” in that time. I then moved them to a garden pond where they have been since February. The largest is now almost a foot long and still growing. I don’t approve of overcrowding fish but temporarily, with good water conditions, the fish can continue to thrive for a temporary length of time. Just keep in mind that an upgrade is needed ASAP.

 

[Jeremy180]

Also keep in mind that crowded conditions means a much bigger water change routine to keep the water healthy.

Pushing the limits like that, I would recommend a good ammonia, nitrate, and nitrite test kit to keep an eye on water quality, liquid, not strips, the strip test kits are notorious for going bead well before the expiration date.

 

[The Lumpfish Guy]

Everyone is going to spit the dummy at me for saying this but you if you keep the water clean (do regular water changes and gravel & filter cleaning), you can keep 3 or 4 small goldfish (about 1 inch long) in a 10 gallon tank for 6-12 months. But you need to keep the water clean and they do better if kept in a bigger tank.

Good argument, I think my point would just be why bother putting them in a 10 gal, you are going to have to buy a bigger tank, save money and their stress (movement ect) and just buy the one larger one to begin with.
I know not always practical, but food for thought.