The anal fin is generally short-based but there are many species with annals exceeding the dorsalin length; some have elongate annals stretching from the anus to the caudal fin, even when the anus is located nearly under the chin, as in the knifefishes (Gymnotidae and Rhamphichthyidae) of South America Flounders (Pleuronectidae) and gouramies (Osphronemidae) are compressifrom fish with long-based annals. Only a relatively few fishes, such as code (Gadidae), have more them one anal fin.Some, such as the jack mackerel (Trachurus), have the anal fin spines separate from the soft rays, forming a small spinous anal. Usually however, if anal fin spines are present, they are located at the