Yes of course they do. How else would they eat and stay alive.
In the front.
They have a big .....
yes
their mouths
Fish open their mouths to breathe by taking in oxygen-rich water, to eat by capturing prey or scavenging for food, and to communicate with other fish through displays of aggression or courtship.
the rare slug fish.
when they are bigger then the fish food or 30 to 40 days Answer I'd just wait till they can't fit in any of the other fish's mouths, fish eat anything they can fit in their mouths.
Puffer fish do not have small mouths. In fact they have a decently large mouth, they need this to fit their large teeth, which they chew on live rock to keep filed down.
Some fish swim with their mouths open to help them breathe better. By opening their mouths, they can take in more water and extract oxygen from it as it passes over their gills. This can be especially helpful in low-oxygen environments or when they are swimming at high speeds.
the difficulties are that there mouths are to small and they cant fit large fish in there mouths so they have more of a chance of going extinct
Yes, goldfish are known to eat smaller fish, especially if they are hungry or if the smaller fish fit into their mouths.
Yes, penguins have mouths for eating and vocalizing. Penguins use their mouths to catch and swallow fish and other prey in the ocean. They also use their mouths to communicate with each other through various vocalizations.