# Assorted Domestic Koi Koi are living history?these carp have been selectively bred in Japan for over 500 years, transformed from humble pond fish into endlessly varied specimens with patterns, colors, and fin shapes that collectors obsess over worldwide. What you're getting here is that same fish, but without the collector's price tag. Domestic koi retain all the personality and longevity of their fancy cousins, just with more modest coloration. They're the kind of fish that will recognize you at feeding time, actively competing for food at the surface and following your hand around the tank?behavior that surprises people expecting a passive, decorative fish. These are sturdy, social fish that thrive when given space to grow and explore. A 100-gallon minimum is a serious requirement, not a suggestion; koi are bottom feeders and active swimmers that need room to patrol and dig. They'll uproot live plants while foraging, so anchor vegetation heavily or embrace the idea of a mostly planted-free setup. Their water needs are stable?slightly neutral to alkaline is ideal?and they're relatively tolerant of temperature fluctuations, though they slow down considerably in cold water. In ideal conditions, you're looking at a 40-year companion, a fish that grows alongside you and develops distinct personality quirks. Tank mates should be chosen carefully. Koi get along with other peaceful fish of similar size, but they'll eventually eat anything small enough to swallow, including smaller fish and shrimp. Goldfish are actually excellent companions?they have similar care needs and temperaments. Plan for regular maintenance: koi are heavy bioload fish that produce significant waste, so robust filtration and consistent water changes are non-negotiable. Feed them quality sinking pellets designed for koi, supplemented with fresh vegetables. This is a fish that demands respect for its needs but rewards you with decades of interaction and growth.