It's probably not the temperature, it's the effects of overcrowding or parasites brought in from the pet store. You need to get a test kit ASAP and test for ammonia and nitrites. If this was a brand new tank, you probably have an ammonia spike going on which is killing the fish. You put a huge heavy load on a small fish tank with a new filter and your ammonia is out of control. Get that test done and get some ammonia binders in there quick.

Are you really in Zone 8? If so, likely you don't need to bring anything in unless you've got tropical turtles and tropical plants.

I think the water is too warm as well. Comets do better at lower temps. The possibility of parasites should be considered. Treat the whole bunch with Clout or something that treats internal parasites. Some external parasites are very hard to see and often leave the host when it dies. Look hard for Anchor worms, leeches and lice. Those can be treated with Anchors away or one of the many other products out there. Sandy

The temp is 76. I just confirmed it. Also just tested Nitrite and Ammonia and both were 0ppm. Would any of the maladies stated above affect goldfish but not the mosquito fish or tadpoles in the tank? I've had bad luck overwintering turtles in my pond. I get a lot of leaf activy in the yard in fall and winter and find the need to clean the pond out quite a few times because of this. Stirring up the pond when the turtles are hibernating has caused me to lose them. Looks like the stirred up muck clogs up their skin and face and restricts their breathing.

Thanks for the suggestions.

Some fish are more resistant to parasites than others. Tadpoles live in the bottom of the pond, in the muck you described. that muck is a perfect breeding ground for parasites and is a very unhealthy thing to have in a pond with goldies or koi. The stress of being moved causes fish to suffer a dip in their immune system, leaving them wide open to parasite attack. More than likely, they died from parasites. Winter is the hardest time for fish. the cold causes their immune systems to not work well. For that reason, a pond should be clean going into winter, not full of muck and hibernating turtles. When you stir the pond up, it is not the muck clogging their faces and gills that cleans them, it is the release of hydrogen sulphide gas that build up in that much that is killing them, or it is parasites. At any rate, you really want to consider a separate pond for the turtles and the fish. Fish need a clean environment and turtles are about the dirtiest critters you can possibly have.

I am not sure you understand my question. My pond is in perfect shape. No problems there. It is my aquarium where I am having problems. I was just telling him why I feel the need to overwinter my turtles indoors.

I do understand your question! your taddies and mosquito fish came in from the pond right? the pond with the muck in the bottom for the turtles? Muck and fish don't mix. The taddies and mosquito fish probably brought in parasites that came from the muck. the goldies from the pet shop were stressed from the move to the pet shop to your aquarium, so the parasites that the skeeter fish and taddies were carrying attacked them.

The real problem gets back to the pond. there is no reason that you could not overwinter goldies in a healthy pond. Overwinter the turtles inside, but leave the goldies outside in a CLEAN pond and they will be just fine. You say your pond is in perfect shape...but you also say that when you stir up the muck on the bottom that fish die. That is not a sign of a pond in perfect shape, but rather a pond that has a serious problem going on.

If your aquarium water quality check outs, then it is almost certain that parasites from the pond are killing the new goldies. Does that make sense?

Didn't read all posts but:

1. goldfish don't need the heat.
2. New tank syndrome - the was has not cycled yet and developed beneficial bacteria and the ammonia is probably very high.
3. Too many goldfish.

Definitely too many goldfish for such a small tank. Goldfish give off a lot of waste - they'll be better off in the pond. They really aren't the easy fish to keep that people think they are. 10 gallons per inch of goldfish is a nice comfortable environment for them - and no other fish. And it's WAY too warm for them. And as comettose says, you need to cycle the tank, then add ONE goldfish, wait a week, add another... If you really want to bring them in, I'd get a separate tank for them. I'm telling you this as someone who learned it all the hard way :-P

It sounds as though I just bought too many goldfish and put them in the tank too soon. Now that a few have died, the balance of the fish seem to be fine. I also dropped the temp a few more degrees. Thanks for the info.

something doesn't add up. Goldfish do not die because they are overcrowded, unless the overcrowding leads to an ammonia and/or nitrite problem. But you claim your ammonia and nitrite readings were zero. Either your test kit lied to you and gave you a zero reading when ammonia really was present, or something else killed the fish.

Then of course, if you bought some of the little "feeder" goldfish at the pet store, they're not really meant to stay alive because they're food for predator fish. They're not pre-sorted into "healthy" and "not healthy". So you can expect to lose a few at the beginning. The ones that stay alive are the strong ones and you can have them for years.

Our original 10 feeder goldies dwindled immediately to 7, which are now - 4 years later? - 7 or 8 inches long and thriving in the pond. They produce more goldfish every spring, and we bring a few babies in every winter so we can enjoy them during the long dreary winter months. They go into a 36 gallon tank with lots of filtration and good bacteria and frequent water changes etc etc.

:) Mary

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Last year I salvaged 15 or so mosquito fish/guppies from the pond and dropped them in two 10 gallon aquariums with a few opal gourami. By mid winter the number was too high to count and the number seemed to be increasing daily. In may the pond was still too cold to put them in although the koi and other fish were active but the mosquito fish /guppies had a population bump that made me think there were easily 1000 fish in there and I started looking for a new container for them until the pond was warmer. Wrong choice. There were three separate die-offs in one of the tanks. I don't know why except overcrowding, so I put them in the pond without worrying about the temp. Most have survived and I see bunches of them hiding in plants and shelves close to the surface. I don't want to deal with hundreds of the fishies dying again even if they are too small to have names. Sandy