Did you put the whole pea in there or did you mush it up into pieces? Splitting it into pieces is a good idea usually lol. Watch it and see if it spits it out, swallows it on his own. If not, I'm not sure. I know some people have gently netted the fish and taken out things stuck in fish's mouths themselves but I haven't done it so I can't comment. Hopefully someone else will chime in. ALso we have an Unhealthy fish section; problems with your fish such as potential illness and things like this might get more answers there.