White Tip Shark Catfish (Ariopsis seemanni)

There is a cautionary tale to be told with Ariopsis seemanni. This gorgeous and highly active species is a tempting purchase for the home aquarium, but, in truth, this is a fish that is not appropriate for the typical hobbyist.

When fully grown, the White Tip Shark Catfish can easily reach or exceed a foot in length, making it a poor choice for smaller tanks housing bite-sized tankmates. And even more troublesome, this species does best long-term in brackish water conditions.

It’s natural range is along the Eastern Pacific coastline from Mexico to Peru, where it can be found in a variety of habitats. Specimens are typically encountered in estuaries—areas where the many rivers in this region empty into the Pacific. However, A. seemanni can also be found in full marine conditions, which is where the species breeds, and in freshwaters, where the males swim to deposit their fertilized eggs. Eventually, the young descend from these freshwater nursery grounds to inhabit the low salinity conditions that they spend most of their lives in.

Juveniles are widely available and hugely popular thanks to their handsome, silvery bodies and shark-like appearance… they even cruise around the bottom in a remarkably shark-like manner. This is really an incredible fish, but, while the juveniles do fine in hard freshwater conditions, successful long-term husbandry is generally said to necessitate a measurable amount of salt in their water. This narrows down the list of suitable tankmates to those fishes which similarly tolerate or thrive in brackish conditions: scats, monos, livebearers, pufferfishes, etc. Or, alternatively, it is possible to acclimate the White Tip Shark Catfish to higher salinity levels and keep it with marine species.

For those willing to commit to providing for the husbandry needs of Ariopsis seemanni, a small group can make for a real centerpiece in a larger aquarium.