Fall colors in fishes: darters, dace and others showing off

Fall has begun the second wave of breeding among the freshwater fishes here at the museum. Both habitariums - the Cypress Swamp, and the Mountain Cove/Stream/Lake - are exposed to natural light 24 hours a day, and also echo the natural temperature fluctuations outside.

The waterfall in the Mountain Cove habitarium

These cues trigger many of the fish species to begin their fall breeding season. Sunfishes, such as the bluegill pictured below, develop vibrant, exaggerated coloration, especially around the head and chest, in hopes of attracting a mate. The males also fan out saucer-shaped nests with their tails which they guard aggressively against rivals. If he is bright enough and has constructed a suitable nest, he might get lucky and entice a willing female to lay her eggs there, which he then fertilizes. The female's job is then done and the male remains to protect all his newly hatched offspring.

A male bluegill, aptly named for his blue gills, is in fine form over a nest

A male pumpkinseed in breeding colors

On the other side of the museum, the trout are also getting anxious to mate. Trout have a similar ritual as the sunfishes but not quite. The male will develop a hooked jaw, or kype, and even a hunched back during mating season, and his nest is called a redd. If he is able to mate successfully, he will fertilize a females eggs over the redd, but both parents will then move on with no further care for the young. 

A large male brook trout in the Mountain Cove exhibit

Many of the fishes in the stream have also begun to "color up". Mountain redbelly dace exhibit astonishing coloration to stand out in the crowd, such as the ones pictured below with rosyside dace.

A closer look at one of the mountain redbelly dace showing his colors

Blacknose dace

A blacknose dace in a shower of bubbles (middle) and a rosyside dace living up to his name

But the dace aren't the only ones showing off in the stream. Many of the darters have also begun to display there breeding colors, such as the also aptly named redline darter (Etheostoma rufilineatum) pictured below.

Vibrant male redlines, such as the one above, have even inspired an elaborate tattoo and other artwork in their honor, as compared to the female redline (pictured below) who is attractive as well, but is not as desperate for attention as her male counterparts.

This adult female redline darter can pick and choose her mate

A dominant male Roanoke logperch (Percina rex) in breeding colors (bottom) chases off two non-breeding colored males.

 

The snubnose darter has many subspecies that can be identified by the patterning of the males. This one appears to be Etheostoma simoterum from the North Fork of the Holston River, VA.