A fish should not look as though it is fighting for oxygen. If you notice that you Oscar has started to struggle with its breathing then there are a few things to do at first. It may still be open from him swallowing the pleco.

Obviously it will have to open its mouth but it shouldn t be a constant opening and closing motion.

Oscar fish Firstly is your water in good condition Even though the tail is now gone from view doesn t mean the fish is all the way down. I d give it some time and keep an eye on him. His mouth being stuck open and not allowing him to eat during feedings will kill him but there shouldn t be a problem if he can still eat. Oscar fish open their mouths wide when they engage in the act of mouth fighting. Although this is most common among two males a male and female often do this before mating. If there are no other Goldfish keeps opening his mouth constantly. By autumn m 6 years ago on cold water fish.

Goldfish keeps opening his mouth constantly. I won a goldfish at the fair last night and i put him in a fish bowl. Today he keeps opening and closing his mouth constantly. I changed the water in the fish bowl today. But he keeps doing it. For a couple days now my oscars have been acting weird. My 8in oscar has been opening its mouth alot towards his fellow oscar and also to me and the glass for no reason. He also pushes bumps into the other oscar. Another thing to add is that i bought some different pellets and tired to

At least for 7-8 hours now my aquarium fish s mouth is stuck wide open. It is still swimming around but unable to eat. I don t think it will live very long if this continues. I just removed him from the tank to b on his own. Any advice on how i can help Fish open their mouths as they swim because they are always searching for food. However this behavior could also mean that your fish is short on oxygen especially if the fish is at the top of