NANFA-- Color patterns on fish

John Bongiovanni (bongi_at_cox-internet.com)
Fri, 13 Sep 2002 20:37:42 -0500

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Sometimes its unavoidable to marvel at the usefulness and efficacy of
color patterns on fish. For instance; F. notatus has that black stripe
looks like a stem in a heavily planted stream. It may even act as a
false water line causing predators to miss. It seems the horizontal
stripe in fish is the most common of camouflage.

Looking at the golden topminnow, the gold specs are the most prominant
feature. At first glance they look more like targets than camouflage.
Every little turn and flick of a fin causes them to glint like chrome
off a '57 Chevy. What protective strategy is in play? Then as to
answer my question one of those little guys swam into a tangle of
Riccia fluitans, Ludwigia glandulosa, Hygrophila polysperma and it
dissapeared right before my eyes. The yellow of its body looked like
the backlit leaves and stems. The gold flecks looked exactly like the
bubbles of O2 emerging from the leaves and stems. This effect was only
evident looking up at the fish from the bottom of the tank as a
predator would.

I caught the fish in thick mats of Elodea, hornwort, Charra and
Potamogeton in relatively cleear water. I would think that those fish
are virtually invisable to sunfish and other predators from below.

John
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