How low can you go, GF, temp.   9/27/09
Hello
I have a black moor and a golden apple snail in a 20 gallon tank. My questions is related to temperature.
<Fire away.>
I see on your sight that it says that goldfish are cold water fish, but it still seems you think they will be happiest at a low temp of 65 degrees from a range perspective.
<They actually have a very broad temperature range. Standard Goldfish (the regular, non-fancy kind without fantails) like Comets and Shubunkins will tolerate 25 C/77 F in summer, down to 4 C/39 F in winter. In the UK, such Goldfish are routinely overwintered outdoors, and provided the pond doesn't freeze solid, they're fine. As you recall from science at school, ice forms and floats to the top of a pond, forms an insulating layer, and so keeps the water underneath relatively insulated and warmer than the ice itself. You need to take some precautions before overwintering Goldfish, such as not feeding them as they cool to 10 C/50 F and downwards, but otherwise they're very tough. Fancy Goldfish though are entirely different...>
However, it also says they can tolerate lower than this when outside in ponds. How much lower, and for how long?
<Non-fancy Goldfish can survive outdoors in the temperate zone provided the water temperature doesn't get below 4 C/39 F for more than 2-3 months.>
For the golden apples, it seems 65 is also a kind of low end of the range, but they will die when it gets colder much easier than the goldfish.
<Indeed. Pomacea snails are subtropical animals and need an alternating tropical period under water and then 2-3 months out of the water where they can aestivate (a summer resting phase). The reason so few people keep Pomacea spp. successfully for more than a year is because they ignore this, and the snails "burn up". There's a good web site, here:
www.applesnail.net
There is lots of information on these snails and what they need to survive in captivity.>
It seems at 50 degrees they will reliably die, but the goldfish will just be 'unhappy'.
<Certainly too cold for Pomacea, and yes, suboptimal for Fancy Goldfish, though Standard Goldfish are fine at this temperature, though they should be fed very little, if anything.>
My tank is in my basement, which is partially heated but gets much colder than the rest of the house in winter. I have not had the tank for a winter yet, so I don't know how cold the water will get in the basement, so I am monitoring it. It was at about 67 degrees over the summer, is now closer to 65 degrees. I would prefer NOT to have to get a heater, even if it means taking the snail upstairs for the season.
My questions are:
How low can I go for the black moor this winter in terms of temperature and still be a "good" fish owner?
<I'd put 10 C/50 F at the low end for Fancy Goldfish. The issue isn't so much the fact their digestive system stops working, since you can avoid that problem simply by not feeding them anything (or at most, letting them eat aquarium plants). The issue is that Fancy Goldfish are prone to blood clots at low temperatures, and these cause particular problems in their fins, and this in turn leads to Finrot.>
At what level is it cruel, and at what point may it die? Even if I do get a heater, I want to keep it relatively cool, and only heat as much as I need to.
<There is nothing wrong with letting them cool down to 10 C/50 F, but if it got much colder than that, you'd want to add a heater. In general though, aim for 15 C/59 F as the optimal wintertime temperature for Fancy Goldfish.>
How low can I go for the snail before it will be truly bad.
<Anything below 18 C/68 F would cause problems. Much better to have the thing aestivate in a damp peat/sand mixture somewhere in a suitably warm spot in the house.>
They say it will die at 50 degrees, but would say 55 degrees still be OK for a few months over the winter?
<Too cold. What is harmless for a few days can be lethal across weeks or months. Think about where an animal comes from, and act accordingly.
Pomacea spp. snails come from places like Florida: that's the climate they're used too.>
If I let the water get colder than 65 degrees, do I need to feed the black moor less, more, or the same amount of food?
<When the water gets cold, feed less, and at or below 10 C/50 F, don't feed at all.>
I realize they are not mammals, but still thought I would ask to see if I should adjust feeding based on the temperature.
<Precisely so. Cold-blooded animals need much less food when they're in their winter resting phase, so their energy requirements are usually met by fat reserves, a handy thing in winter when there's no food anyway. But also remember their enzymes and digestive tract muscles aren't working much either, and food that sits in the gut unprocessed will rot and cause infections.>
Thank you so much
<Cheers, Neale.>

Re: How low can you go  9/27/09
Wow, thanks, the longer I own these fishes the more I feel like a scientist in training.
<Like should be one long science class. Kinda, sort of, anyway. If you're learning new stuff about the world around you, that's a good thing.>
I sometimes feel caring for my cat is less complex than my goldfish;)
<In some ways yes, in other ways no. Fish are more "different" to us than cats, so there are more differences to consider. On the other hand, fish are essentially tougher and longer lived than mammals of similar body mass, and provided their basic needs are met, they don't get ill and they're much easier to look after through vacations.>
I'll checkout the snail sight as well. I doubt I would get a snail for my goldfish tank again knowing what I know now.
<I actually don't recommend people mix Apple/Mystery snails (Pomacea spp.) with Goldfish for a number of reasons, and this is one.>
It sounds like your advice for the black moor is that if it is in a range between 51-59 degrees in the winter I should not feed it much, but continuing to feed normally it if 60 degrees and above.
<Correct. During the winter, leave some green plants (like Elodea/Pondweed) in the tank, and if it gets hungry, it'll eat. Couldn't be simpler.>
At 50 and below it would be bad for the moor, but I should not feed it at all if it slips down to that range until I can heat the water higher.
<Certainly, don't add any flake or pellets.>
Can you define not feeding it much? Lets say it is at 55 degrees for 3 months.
<At that temperature, feeding flakes or pellets 2-3 times per week would be fine, but the rest of the time just Pondweed. If in doubt, feed less rather than more. Pondweed can keep a Goldfish happy for months on end, if replaced as required. Given how cheap this stuff is, it's really very easy to look after them this way, and the mystery is why people don't bother!>
Would I feed once a week? Once a month? Any kind of food better than another for any special winter feedings?
<Plants! Cheap aquarium plants are safe foods for the 3 months when its cold. Here in England, pond fish are essentially only given flakes or pellets from about March or October. The rest of the time Goldfish eat whatever algae and plants they find under the ice, should they want to eat at all. When cold, they're in a semi "suspended animation" state, and really don't get hungry. If it warms up a little in winter, they'll eat some algae or whatever, but that's about it. So, in a cold, basement tank, be very cautious with food, and once the water gets very cold, don't offer flake at all, just Pondweed. Cheers, Neale.>