Muraena anguilla.
The Eel.

Title: D. Marcus Elieser Bloch's, ausübenden Arztes zu Berlin ... Ökonomische Naturgeschichte der Fische Deutschlands : mit sieben und dreyssig Kupfertafeln nach Originalen
Year: 1783 (1780s)
Authors: Bloch, Marcus Elieser, 1723-1799; Krüger, junior, ill; Schmidt, Ludwig Carl, engraver; Schmidt, Johann Gottlieb, engraver; Schmidt, F. G. , engraver; Bodenehr, G. , engraver; Darchow, C. , engraver; Berger, F. G. , engraver; Schmidt, Friedrich Wilhelm, engraver; Schmidt, A. F. , engraver; Gursch, C. F. , engraver; Baird, Spencer Fullerton, 1823-1887, former owner. DSI
Subjects: Ichthyology; Fishes; Fishes
Source book page: https://archive.org/stream/dmarcuselieserbl00bloc/#page/n152/mode/1up
Author Marcus Elieser Bloch, 1723-1799; Krüger, junior, ill; Ludwig Carl Schmidt, engraver; Johann Gottlieb Schmidt, engraver; F. G. Schmidt, engraver; G. Bodenehr, engraver; C. Darchow, engraver; F. G. Berger, engraver; Friedrich Wilhelm Schmidt, engraver; A. F. Schmidt, engraver; C. F. Gursch, engraver; Spencer Fullerton Baird, 1823-1887, former owner. DSI
Source: https://commons.wikimedia.org/wiki/File:D._Marcus_Elieser_Bloch%27s,_aus%C3%BCbenden_Arztes_zu_Berlin_%C3%96konomische_Naturgeschichte_der_Fische_Deutschlands_-_mit_sieben_und_dreyssig_Kupfertafeln_nach_Originalen_(1783)_(20796085209).jpg

The European eel or common eel (Anguilla anguilla) is a species of eel, a snake-like, catadromous fish. The European eel, Anguilla anguilla, is one of 19 species in their genus, found in the Northern Atlantic south to Mauritius, the Mediterranean, North and Baltic Seas and the rivers that feed into these ocean bodies.