Wild Profile: Meet the pumpkinseed sunfish

A male pumpkinseed sunfish guarding its nest By Glass and Nature/Shutterstock

If there’s an award for Prettiest Ontario Fish, the pumpkinseed sunfish should at least place somewhere on the list. Henry David Thoreau once said it shines like “a brilliant coin fresh from the mint.” With a name like “sunfish” it’s no wonder that this flat, two-dimensional fish only moves to shallower water when it’s sunny out. The pumpkinseed sunfish is such a Nervous Nelly that if a shadow passes overhead, it’ll dart to the safety of deeper water.

Pumpkinseeds prefer weedy, warm waters. It’s the male fish that do the prep for upcoming offspring. They get to work on a nest once the water heats up to about room temperature, sometimes as late as July. They’ll sweep their tails back and forth on the lake bottom, clearing a depression. Then they’ll pull out weed roots to form a circle about twice the size of their bodies, as long as 20 inches. Pumpkinseed sunfish nurseries are made up of 10 to 15 nests, with groups of male fish working together.

Watch this video of shimmering “rainbow” fish

A pumpkinseed doesn’t get paternal until he’s on the older side—six or seven. Young fish, on the other hand, are known cheaters. They’re about a third smaller in size, but very sneaky. A young male will sidle up to a nest and then shoot his own milt into it. This means the fish that actually built the nest can end up unknowingly tending to children—a lot of children—that aren’t his own.

One male can accumulate 15,000 eggs in his nest. His parenting mostly involves fanning the eggs with his tail non-stop—this keeps them aerated—and protecting the nest from intruders. Once the eggs hatch into tiny fry, Dad takes care of them for another 10 days or so, until they swim away. Goodbye, Father of the Year!

Did you know that fish have been schooling for 50 million years?

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