I have read this link which explains how to say that something is n-times as big as something else. My sentence doesn't quite fit these patterns.
A fish has just been caught (no mention of size). The next sentence is:
So, I think it's supposed to be saying
(the fish just caught) seems three times as large as the long, thin fish swimming along the river bank.
But there is no adjective in this sentence. So I don't really know if it's bigger, smaller, fatter, or whatever. Is there a clue in the grammar I'm missing that makes bigger the obvious choice? Or, must I just infer it from context (though, I don't think the context makes it particularly clear)?