That means your fish is ill
no
Around 10dGH is good but they will be OK anywhere from 5 to 20.
Well, first, your eggs should be in a separate tank from all the other fish, ok? Then, when you clean the tank with the goldfish eggs, I usually never clean out the water completely. I usually just dump out 25% of the water and replace it with clean water. I'm sure no harm to the goldfish eggs will be done if you do partial water changes, and partial water changes are all you ever will need. However, if you REALLY need to clean out the tank completely, usually goldfish lay their eggs on aquatic plants or objects. If you move the plant or the object to another little tank or a safe place while you clean out the tank, I'm sure there will be no problem. When your done, just replace the plant/object into the finished tank.
Goldfish cannot live in bowls. Fancy goldfish need at least 20 gallons for the first fish, and 10 gallons minimum for any additional goldfish. This means that for two goldfish, the smallest tank you should have is 30 gallons.
Yes as long as it can't fit in an other fishes mouth it will be perfectly fine. A fishes tank can never be too big.
The only fish I know of that is called a celestial is a type of goldfish. If that is the case then most other fancy goldfish would be OK as companions provided the tank is large enough. A single goldfish needs at least 10 gallons of water to live reasonably well.
If they are fancy goldfish (the plump looking ones) then 6 or so would do well in an 80 gallon when fully grown if they are common goldfish, then 2 maybe 3 when full grown would be ok as they reach a whole foot long! This may seem like its not many fish for a large tank however goldfish are real poo machines and good filtration is a must.
Yes. It should be fine. I have 2 regular goldfish living with a bubble eye goldfish and to fancy fantail goldfish, so I think it will be okay.
no goldfish and tropical fish cannot live together. gold fish are cold water fish and tropical fish are tropical fish. also only 2 goldfish can go in a 30 gallon, because goldfish make a lot of waste.
Firstly, hopefully you do not have goldfish in the 'goldfish bowl' as they need at least 20 gallons for one goldfish. That being said, you can add sea shells to a tank provided that you have washed the shells clean with one part bleach to 19 parts water (1 cup of bleach to 19 cups of water), rinsed the shells very well in water, then soaked it in treated water (water that you have added Prime or Amquel to for example) before adding them to your tank.
the answer is nothing ok
if hes back in and seems ok, yeah. Just make sure you get a lid so he doesnt do it again when you not there or he'll die because they cant breathe in air >_<