Aristotle's Catfish

Silurus aristotelis holds the distinction of being one of the first fish ever scientifically described — Aristotle recorded it in his natural history writings in the 4th century BC. It is endemic to the river systems of Greece, including the Acheloos, Sperchios, Aliakmon, and Axios, and does not naturally occur outside the Balkan Peninsula. Though smaller than the Wels, it reaches at least 200 cm and is the top freshwater predator in its native rivers.

Its biology and captive requirements closely mirror those of S. glanis — cool, well-oxygenated water, very large tank volume, and a diet of whole fish and meaty prey are all essential. It is somewhat more cold-tolerant than most tropical catfish species and can be maintained in unheated European fishrooms at temperatures as low as 12°C. Like the Wels, it is strictly a public-aquarium or large indoor pond fish at full size.

As a species of both conservation and historical significance, S. aristotelis is protected in parts of Greece and collecting must be done responsibly. Captive-bred specimens are occasionally available from specialist European breeders. Its historical importance and rarity make it one of the most culturally significant freshwater fish in the hobby.

Water: 12–24°C, pH 6.5–8.0, moderate hardness; cool and well-oxygenated. Tank: 5 000 L minimum; cool water system or unheated European fish room. Feeding: Whole fish, large prawns, earthworms; robust carnivore diet. Breeding: Spring nest-spawner with male guarding; requires large space and cool seasonal cycling. Compatibility: Apex predator — keep alone or with fish far too large to be eaten.