Goldfish

[JeffP]

Actually there is a rational explanation why fancier goldfish benefit from higher temperatures. The fanciest goldfish are are the ones that typically carry the most mutations and have undergone extensive linebreeding. Linebreeding reduces genetic variability which results in reduced vigor. That's why you hear about fish breeders occasionally outcrossing with an unrelated strain or wild type to introduce new genes and increase the vigor of their strain. The downside from the breeder's perspective is that offspring will temporarily be more unpredictable and there will be fewer fish with the desired traits. Goldfish demonstrate polyploid genetics which makes this really a mess (at least for me).

Anyway as you proceed from common, comet, shubunkin, ryunkin, oranda, lionhead, ranchu, veiltales, bubbleyes, etc. the fish get progressively less hardy and benefit from higher water temps. I heat my ryunkin/oranda tank to 74F.

Goldfish are not only messy but they are also oxygen hogs. So with increased water temps it becomes critical to oxygenate the water with air stones and good water movement.

IMO, a big negative for mixing tropicals and goldfish is that their disease "profiles" are different. Although your goldfish will probably survive with the tetras (assuming the tetras don't fin nip), it is not recommended to mix them. Goldfish are omnivorous so large ones will certainly munch on fry and small fish like neons (if it can catch them). However, they are not a predatory fish so it's more of an opportunistic thing.

Good luck

 

[aquariaddictus]

Hey, Jeff, that was interesting. I just read an article in TFH that talked about tropicals that could live with goldfish at the LOWER end of the temp spectrum - sort of the opposite of what we're talking here. White clouds and zebra danios, according to this article can take (and the white clouds spawned) temps down to 60F. This was in reply to someone looking for tankmates for GF who wanted to keep a cooler temp. (TFH, p 23, Jan 2003)

So it would stand to reason that they all (GF, white clouds, and the danios) could live comfortably somewhere in between.

judy

 

[BigFishDude]

Wow, you learn something new everyday. Thanks for the explaination Jeff

 

[Whistler225]

my tanks

to those asking about mixing goldfish with tropical fish: I have kept common, comet, and fancy goldfish (Oranda) in tropical community tanks successfully for several years. Right now, my 29 gallon tank has two common, one comet, one ornda, two pleco catfish, and four serpae (red minor) tetras in it. I think the main trick to having these types of tanks is the same trick to having a happy tank in general: proper set-up and maintenance. My tank is heated to 78 degrees, and the goldfish are all quite happy. They come to the front of the tank and play any time I get close, and they behave around the other fish. I have a variety of ornamentation in the tank, providing places for the tetras to hide in when necessary while giving the goldfish plenty of room to swim. One interesting thing I didn't expect was that my goldfish all school together. The Oranda is the clear leader and the other three follow him around the tank while feeding. The tank is well supplied with oxygen, and I perform regular water changes to keep the amonia level low. I have kept many goldfish in heated tanks with no problems, with many other types of fish (once I had three comets and a Black Ghost Knife in a ten gallon tank, which I had to give away when my company sent me out of town a few years ago. Those fish were moved to a 55 gallon tank later, and after three years, they are all still alive and very happy, and the Black Ghost is about 18 inches long!) At any rate, I think a serious aquarium hobbyist can successfully keep goldfish and tropical fish together, as long as you pay attention and do what you need to do as far as maintenance is concerned.

 

[aquariumfishguy]

Water changes shouldn't be to "keep the ammonia levels down", they should be done to reduce nitrates. While I, too, keep my goldfish tanks with heaters, I think 78*F is pretty darn warm for commons (or comets). Also, I have friends who upgraded their common goldfish to a 55 gallon after their 30 gallon tank was too small for the fish... so while I hope your 29 gallon tank works out for you, I am doubtful that any of those fish will reach their maximum potential length in such a cramped area. Furthermore, 3 years isn't long enough to get a good feel for how these fish will turn out. They live for over 15-20+ years.