Monday, May 27, 2013

Successful reproduction of Rainbow shiners in captivity

The Rainbow shiner, (Notropis chrosomus) is a stunning species of freshwater fish that rivals even the most beautiful species of tetra, or tropical marine reef fish.  This peaceful, schooling fish grows a little over 2 inches and can be found thoughout much of central Alabama and northern Georgia.  While the Rainbow shiner can be found in the same habitat as the Tangerine darter (see previous post), this species is much more tolerant of higher temperatures typical of the Southeast.






This is a male adorning his bright pink pigmentation
along with some stunning, electric blue.
 
 
In May of 2012, I took a trip down to Tuscaloosa, AL to collect a few Rainbow shiners for display.  At the time, the fish were nearning the end of their breeding season but were still brightly colored.  After a long drive back to Washington, D.C., the fish were held off exhibit in order to be quarantined.  This allows us time to monitor the fish for any signs of disease and prophylactically treat them with various drugs to rid them of any internal/external parasites.  Eventually all of the adults made it onto display in our "Southern Stream" exhibit.  There, they live alongside other species of stream fish that are commonly found throughout the South.  Such species include, the Blackbanded darter (Percina nigrofasciata), Alabama darter (Etheostoma ramseyi), and Alabama shiner (Cyprinella callistia) to name a few.  Several months past and I began to notice a few of the males coloring-up....a sure sign that they were getting ready to breed.  While working one weekend in late February, I nocticed several of the Rainbow shiners were spawning with one another between some large boulders in the exhibit (first picture below).  Typically these fish, like many shiners, will lay their eggs on a Chub nest.  (A chub is a much larger species of stream-going fish that collects quarter sized stones into a large mound).  After watching them for several minutes, I decided to carefully collect, and rear the eggs.  The video below shows the fish in action.
Here you can see some males luring females
with their bright colors, to breed.
 
 
 
After about a week, the fry hatch out and sit on the bottom in order to finish absorbing their yolk sac.  During this time, the fry do not feed.  The picture below show the fry just after they became free-swimming:
Age: 8 days post hatching.  Size: ~5mm.
 
Age: ~2-3 months.  Size: ~1cm.  You can see their stomachs
are full of artemia nauplii .  Their orange pigmentation is
just starting to develop above the black, mid-body line.
 
Age: ~6 months.  Size: ~1.5 inches.  Even though this young
individual won't be ready to breed for another several months,
you can clearly see the bright colors typical of this species.
 
 
As you might imagine, Rainbow shiners have become quite popular among native, freshwater, enthusisasts and are commonly bred.  While this species has not gained popularity in the pet trade, there is a growing demand for this species across the Atlantic in Western Europe where the Rainbow shiner is considered "exotic"!