Fancy goldfish growth rate? 20 Gallon Tank

Discussion in 'Goldfish' started by fishies123, Apr 4, 2010.

  1. fishies123New MemberMember

    Hi, everyone. I've been trying to decide what to put in a new tank that we got. I was told it was a 29 gallon, then thought it was 25. We measured several different times, and after doing the glass thickness too, we realize it's only 20. Anyway, I want to get a fancy goldfish. I know they need 30 gallons or bigger when they are full grown, but how quickly do they grow? A guy at Petsmart told me that I could keep two in a 20 gallon for about 5 years. I'm not sure if I believe that. I know I will need to upgrade eventually, but can someone please tell me from experience how quickly they grow so I can plan things out? I've heard that they grow a couple inches a year, but I've also heard an inch a month. We have 2 filters that add up to 50 gallons of filtration. If I get two babies, will they be okay for a while? Should I just get one? I want probably a fantail, maybe a Ryukin, but not an Oranda. Thanks!
  2. ButterflyModeratorModerator Member

    Welcome to fishLore!
    We try to recommend 20g for the first goldfish and 10g for each additional goldfish.
    The reason being they are really heavy waste producers and they need to be given space to grow. different fish grow at different rates but the better the water quality is the faster they will grow and the longer they will live.
    Here is a profile on goldfish maybe it will answer some of your questions.
    Let us know if we can be of any further help.
  3. e_watson09Well Known MemberMember

    Generally I personally think while they are small you can keep one in a 20gal and then 10gal for each additional. Each fish will grow at different rates so there really isn't an answer to give you. My guess is for just one in a 20 gal you'll probably have to upgrade tanks or trade the fish in within a year or so.
  4. gremlinWell Known MemberMember

    Goldfish grow depending on the size of the tank they are in and the temperature of the water. My sister's goldies spawned last summer and she moved all the babies to a 200 gallon inflatable swimming pool to keep them safe from the adults. The babies that were hatched at the beginning of the summer and had all summer to grow were a good 5 - 6 inches by the time cool weather rolled around (3 months or so). The babies that hatched at the tail end of the summer and only had about 2-3 weeks before cooler weather only got about 1-2 inches.
  5. fishies123New MemberMember

    Okay, so I did some more research. So Gremlin, if they stay small because of their tank size, is that okay for them? I read some stuff about growth hormones that they use to try to stunt the other fish, but if the tank is too small the hormones stunt their own bodies, too. Then some people say their organs keep growing so this is why they die. Other people say it's not harmful for them to stay small. So now I'm wondering, is it better to get one or two? Because if I have two, they will stunt each other's growth, which may either be good or bad depending on if the organ thing is true. If I have one and there are no other fish then it won't release the hormone and that one fish will get huge, right? Just trying to understand how this works.
  6. JayseeFishlore LegendMember

    My girlfriends fancy, bug-eyed goldfish grew to the size of a baseball (just the body) living in a 10 gallon tank for 4 years. It was barely able to swim. Most of last year was spent in a 29 gallon tank, and we both think he has grown a little.
    Last edited: Apr 6, 2010
  7. Red1313Fishlore VIPMember

    I think that the quality of the fish need to be taken into account as well.

    I've had Charlie for a few months now and since I see him every day I'm not sure how much he's grown but all my friends always comment about how much he's grown. On the other hand I have my "Special Boy" Sam, and Sin as well and they don't seem to have grown much.

    Fish will grow faster in clean water, smaller water volumes are typically not as "clean" as larger volumes despite water changes simply because there isn't as much water to dilute waste (ammonia, hormones, etc.). I'm not sure I understand what you're asking...
    In the tank you have 1 fancy goldfish would be great. Two would be tight, and eventually (one year or two) you'd probably want to upgrade to give them more room.
  8. fishies123New MemberMember

    Thanks, Red. What I was asking was, someone told me that when there's more than one fish in a tank they give off a hormone to try to make the other fish smaller. If the tank is small, they are both affected by the hormones, which means they are both stunted. I've heard this is bad because their organs keep growing. This also means, though that if there's only one fish in the tank that fish will get huge quickly because there are no growth hormones from itself or any other fish, and I wantd to know if this was true.
  9. Red1313Fishlore VIPMember

    In regards to that specific question there is actually very little scientific data (I know I was going to write an article on it). Water quality seems to be the main issue rather then tank size. Fish breeders report that spawns moved from 1 10 gallon tank (for example) into 2 10 gallon tanks will grow faster then if they are kept in the original 10 gallon tank. Fish kept in too small a tank won't "stop" growing but they will slow. Poor water quality and stress can lead to permanent stunting, but in some of the very large species (think pleco's, Arrowana, etc.) They may eventually develop physical deformities (imagine having to spend most of your life hunched over because the ceiling is too low). Gremlin's report of the pond fish growth rates is accurate but a friend of mine bought a feeder goldfish from Petsmart 2 years ago now and has kept him in a 10 gallon tank the whole time. He is maybe 4" long to date. However he isn't a pretty goldfish and I can't say if that's because of the type of fish he is or if it's because of his living conditions.

    Don't know if that helped answer your question more or not...
  10. gremlinWell Known MemberMember

    It really isn't good for them to be kept in a small tank just to try to keep them small. I'm not really sure about the stunting the insides or not since I have not ever dissected a fish that was stunted. I do know that a fish kept in too small of a tank, even if it is alone, can become deformed. I do have personal experience with this. An acquaintance had a friend who had a goldfish in a "bowl" that "looked funny". It was a feeder goldfish that the child in the family had won at a school fair. When this acquaintance finally brought me the fish, the poor thing was so far gone I was unable to save it. It's spine was bent in three different places, it had a huge bulge on it's side and belly, and the tail was bent down and to the side away from the bulge. I can only assume that the damage was done because the goldfish did not have room to grow. The parent that had the fish said that the fish "looked like a normal fish when we got it, but it changed as it grew." I don't know how long they had it, or what size bowl it was in, or any other details of it's care - all I know was the end result was not good for the poor fish.

    I have read somewhere that fish emit a hormone into their environment and read the level of the hormone in the water. The concentration of the hormone tells the fish how many other fish of it's species are in the area. I do not know if it would cause them to slow their growth or not.
  11. ElvishswimmerValued MemberMember

    I've heard about fry causing other babies to grow slower... They called them hogs.

    I also read one fry diary where the person documented the fish from fry to adulthood.

    Over the course of 6 months these fish went from eggs, to 6 inches long and ready to spawn again! They look like Ryukins.

    So there are a lot that go into what makes a fish grow or not, but you don't really want to stunt their growth.
  12. fishies123New MemberMember

    Thank you everybody for your responses. For the record, I never wanted to stunt their growth on purpose. When I asked Gremlin if it was okay for them to end up smaller, I was just asking for clarification on what everybody was trying to say, but I wasn't ever planning to try to stunt mine. I was trying to make sure that I wasn't stunting them : )