Koi Fish Information Centre

Her growth likely slowed down to the stunting that is taking place from being in the undersized tank. There’s a chance she’ll start growing again once she’s in the 55G but even the 55G is too small for a long-bodied goldfish since it doesn’t give them much swimming room. She likely will not reach full size in a 55G either but it’s certainly nearly a 100% improvement over the 29G so as long as you keep up a frequent PWC schedule and take other steps to improve the ecology, you’ll be giving her a much better chance at living a much longer and healthier life.
A 55G is OK for one or two round-bodied goldfish since they are not as much of swimmers but weekly PWC’s and tank/filter maintenance is still needed since round-bodied goldfish still have very similar body mass to the long-bodied variants.
While it’s true that most fish will self-stunt themselves so they do not outgrow their homes, this stunting process also causes a lot of stress to the fish which ultimately leads to health issues and a much shorter lifespan.. and could be a reason why your fish is so jittery. The stunting process which is caused by various hormone levels in their water, is not something us hobbyists can test for but by reading scientific reports done for the fisheries industry, they’ve learned that by doing LOTS of water changing and using advanced filtration (something else we do not have yet), they can remove/dilute/flush out these hormones so the farm raised fish, who are grossly overstocked as well, still grow at a rapid rate so they can get them to market at the largest size possible in as short a period of time… otherwise we wouldn’t have an abundant supply of affordable fresh fried catfish fingers or your other fish meal du jour!
If you’ve been reading all of the other threads out here, you will have seen us recently discussing water bridges, U-tubes, etc. as ways to connect two tanks so that you increase the total water volume of the system. This allows for better dilution of hormones and waste in between the weekly tank/filter maintenance. Also, if you were to connect the two tanks, you could turn the 29G into a planted tank and even put in a school of minnow type fish like zebra danios, white cloud mountain minnows, etc… or I think you might have been talking about dwarf killifish or something as long as they do OK at room temperatures. That would add very little bioload to the system, yet still give you “life” in the 29G… and still allow the goldfishes waste and hormones to be diluted and naturally filtered by the live plants in the 29G. While a water bridge would allow the fish to swim between the two tanks, you do not really want this since your bigger goldfish might look at the minnow type fish as snacks.. so the U-tubes with filter intake screens on them would prevent fish from moving between the tanks and are much less expensive.
If you do not like this idea, then you could still add certain live plants to the 55G which would help with the overall ecology of the tank and since you say your goldfish is shy, the plants will afford it a better sense of security.
Are you doing proper filter maintenance also? Waiting too long between doing filter cleaning will not only clog up the filters but also start allowing the detritus to break down and go into solution called DOC’s (dissolved organic compounds) or TDS (total dissolved solids), neither of which are good for the fish since they have to breathe these things… much like us humans shouldn’t be breathing a lot of the junk we breathe. My blog has a long article on filter maintenance.
Lenny Vasbinder Fish Blog - http://GoldLenny.blogspot.com (Links to any articles referenced in above reply are listed on the right side, alphabetically under Labels and also under Archives by Year, Month)

Category: Philippines Internet Koi Society