Goldfish have pharyngeal teeth which are near the back of the throat, so they may chew their food in some way, but not the same way that humans or animals with normal teeth would
Its mouth
if the goldfish's mouth couldn't open then it wouldn't be able to eat and it would end up dying.
If you mean that if they come from their mouth or their bottom, it's bottom
a) Goldfish (all fish) breathe through their gills b) All fish (Including Goldfish) suck water in through their mouth and pass it through their gill filament's.
Before I tell on a goldfish, I try to work the problem out with the goldfish. If I cannot work out the problem, I generally tell the goldfish's Mother or Father in person.
Bettas and goldfish
Guppies don't get large enought to eat goldfish. They will eat anything they can fit in their mouth. The goldfish might eat your guppies though.-Melchisedek
It depends, if your goldfish are smaller than your algae eater, and big enough to fit in it's mouth, then very much so. If the goldfish are small, but too big to fit into your algae eater's mouth, then he might just injure them. But your algae eater shouldn't be so small that your goldfish could eat it. The rule with fish that I always go by is, if it can fit into it's mouth, it will be eaten.
They don't. The constant 'Mouthing" is how they breath.
No the male will eat them keep them separate them until they can't fit in the mouth of the goldfish.
A goldfish's breathing rate can be determined by counting the amount of times the goldfish opens and closes its mouth within a set amount of time, ex. 92 breathes per minute.
yes unless the zebra danio can fit in its mouth