Does he seem to be able to breath ok, presumably eating is off the cards? If it looks really wedged, then manual removal might be the only option.
If it were mine, I would net it using two nets to keep it quick and simple, and reduce the chance of making him startle and bash his face on something and possibly do more damage/push it down further.
You can handle the fish with a wet cloth/net which will mean you can grip quite securely then. However, I would have a go with a pair of tweezers with the fish netted, but still under the water first. Should give you enough time/space to pull it out. Only remove the fish if it is REALLY jammed, and you cannot do it the other way.
Looking a the pic it should be fairly easy to remove, lots of it sticking out.