The Inverted World of the Upside-Down Catfish
If you keep these interesting catfish, choose tankmates and aquascape based on their needs.
By
Stephen G. Noble |
A fish swimming upside down normally indicates a serious ailment and a near-term appointment with the Great Aquatic Paradise. But one unusual fish, the upside-down catfish (Synodontis nigriventris), is quite adept at gracefully gliding upside down with the greatest of ease. Due to a remarkable physiology, the seemingly bizarre swimming habits of this fish are actually quite normal, rather than being an indicator of a life-threatening illness. These fish are able to perform underwater acrobatics, including knife edges, barrel rolls and their extended namesake posture. In a still aquarium, these fish are able to remain motionless in an upside-down position for what seems to be an indefinite period of time.
Synodontis nigriventris received its Greek and Latin binomial names from its tooth and jaw formation, and unusual dark belly coloration. The genus name Synodontis means “together teeth,” and the species name nigriventris means “dark abdomen.” Normally, the dorsal pigmentation of a fish is darker than the ventral side, and it is speculated that this is to provide visual obscuration from predators. But the ventral side of the upside-down catfish is dark, indicating this fish has chromatically adapted camouflage for extended upside-down swimming near the water’s surface.
Want to read the full story? Pick up the November 2010 issue of Aquarium Fish International today.
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The Inverted World of the Upside-Down Catfish