Goldfish - Oh dear.

[unicorn]

Ds's fish has died overnight and seems to be stuck to the filter.
We only got it on Wednesday (had prepared the tank since Saturday)
Any ideas why it has died and is the other one (dd's) likely to pop it soon.

Also how do I remove it from filter?

Ds rather upset.

Turn the filter off and you should be able to remove it.

Many reasons why it could have died. I lost a million fish to white spot, fin rot, mouth rot and various other things. Tried everything in the book before I gave up and decided to stop threatening goldfish with extinction.

Sorry unicorn, hope your Ds is a bit better.
There are so many reasons it seems while goldfish kick the bucket, and as a goldfish-owning household, I'm none the wiser.
Am currently treating the second for fin rot (1 week after we successfully treated first for finrot).
Don't know about anyone else here at home, but I'm really fond of them so am hoping to steer them through this rot phase!
I think the tank can be 'quarantined' if a fish dies, if you google it you should find some info.
Good luck!