The Roman aristocracy had such exorbitant needs that it even built ponds (piscinae or vivaria piscorum) on its enormous property, in which various species of fish lived, including moray eels.
The main purpose of Roman nobles was to ensure a supply of fresh fish, which was simply caught from ponds and then served to eat. The species of fish that could be bred and fed were being competed.
Ancient Romans realized that you should not keep all species of fish in one tank, because they could eat each other. Among others, Columella (c. 4 – c. 70 CE) – the author of works devoted to agrotechnics – mentions that it is advisable not to keep aggressive moray eels in one pool with other fish, because simply speaking they will eat them1. Athenaeus (2nd-3rd century CE) – a Greek rhetorician and grammarian – warned that moray eels could even attack a fisherman who wanted to catch them2.
Pliny the Elder mentions that the moray eel (muranea) was bred by Roman nobles: Lucius Marcius Philippus, Quintus Hortensius, Gaius Hirrius or Lucius Licinius Lucullus and his brother Mark. The first of them to grow moray eels separately was Gaius Hirrius3. Lukullus, in turn, became famous for its beautiful gardens – following the pattern of eastern patterns. Interestingly, he ordered, inter alia, dig a canal through the mountains near Naples to provide sea access to its pools and mix fresh and saltwater. This way, he could keep sea fish in his gardens. Through his actions, he came to be referred to as “Xerxes in a toga”, referring to the famous Persian commander who had the canal dig through the Athos headland so that his fleet could pass.
Coming back to moray eels – they were so valued that reportedly Marcus Crassus or Hortensius, having learned that their favourite moraines had died out, they experienced it very much and even cried.
Finally, it is worth mentioning a certain Vedius Pollio, the son of a liberator who was famous for his bad handling of slaves. Apparently, Vedius Pollio threw rebellious slaves into a pool of moray eels as a punishment for their misdeeds (including breaking a cup)4.