Dinner time with the ultimate eater....

For us as humans we find dinner time as an aesthetically pleasing routine, supplementing with snacks throughout the day. For the Astyanax jordaniFreshwater brine shrimp species, however, dinner time is used for sustaining another day. This genus is made up of both herbivorous and omnivorous species, however, the specific species A. jordani is only found to be omnivorous, feeding on small aquatic animals in the benthic layer and vegetal items (both autochthonous and allochthonous) (Manna and Mazzoni 2012). When venturing down into dark waters, one doesn't know what they will encounter. Because many animals that live in the benthic layer lack pigmentation, they may not stand out against the substrate like we'd imagine. Many of the small organisms that are meals for the Blind Cave fish are fairly difficult to see because of their size. For example, small shrimp species that live in freshwater systems may not show up in our field of view when under water. Although the Hell Creek Cave Crayfish is not prey to the A. jordani, it has traits similar to the species that it preys on because it lives in freshwater caves and also possesses many morphological similarities. Take a look HERE to learn more about this arthropod.

Studies that were done with many different species in this genus have shown that their interactions between different substances in their diet fluctuates based on the time of year and also because of the resource availability. Following the wet and dry seasons data has proven that the fish are introduced with the largest availability for resources. The preceding months generally have lower availability and so that diet of the species will differ and change to a more distinct niche. Obviously, during the rest of the months they will have a more overlapping food niche when resources are more abundant (Esteves and Galette, 1995).

Hurricane Track Map of Gulf of MexicoTrophic plasticity is a very important trait to have if you want to stick around in a competetive environment. Luckily for the A. jordani, these fish are said the have this plasticity due to their ability to acquire different resources and use them depending on environment conditions, such as weather patterns mentioned above. Because they have such a high plasticity, one can conquer that they will have a better chance of survival in extreme changes in their habitat, unlike those who are less tolerant of diet change (Manna and Mazzoni 2012).

On a side note....because this fish is a common starter-fish for fresh water aquariums there are a lot of commercially prepared food that it will eat. Generally, you want to be able to give this fish a mix of meat and vegetation and so an example food mix would consist of: brine shrimp, bloodworms, tubiflex worms, and flake foods. For other examples of food to feed, check out this aquarium store:
That Fish Place.

Go back home!                                Feeling full on knowledge? Move on to reproduction HERE!

Want to see other organisms created by UWL students:
Check out