"There is one shrimp left on his plate."
Translation:Il reste une crevette dans son assiette.
Honestly, I don't really know why. "sur son assiette" is the literal translation of "on his plate" but in this case we never say that but "dans son assiette". I think that's because a plate is made to be a container and you don't put things "on" a container but "inside" a container so you say "dans" and not "sur".
il reste + [substantif] → "there is some (noun) left".
While your sentence does appear to translate to one given, I can't say wherever it is commonplace to use it this way in French.
I do know that "laisser " can be used with reference to food, such as
Si tu n'as plus faim, laisse ton dessert. → "Leave your dessert if you're not hungry."
However, I feel the construction you used has a sense of forgetting something and leaving it somewhere. As in:
J'ai laissé mon sac chez ma mère. → " I left my bag at my mum's."
But we really need a native speaker to wade in on this one.
it is good translation propose by DL
it is necessary no to mixed up the use of these verbs in this context " laisser " and the verb " rester "
il reste une crevette sur ( dans ) son assiette translate by the verb to be left in english !
il laisse ( something ) active
il reste ( something ) passive