I first acquired F. nigeranius
from Bill Gallagher (BAKA) on
March 18, 1998. Originally, I had them in a 20 gallon tank with a couple of
mops. The fish flourished. I dutifully picked, incubated and raised the fry.
Soon I was in the possession of lots of F. nigeranius
More fish, more mops, more eggs, more work. Oh my!
I decided it was time to move to a less intensive arrangement. So, I set up an 80 gallon
vivarium. Since I enjoy growing aquatic plants, I decided to
as a substrate. This is a clay-base material that is widely used
in major league baseball as well as golf courses throughout the U.S. It has several
advantages to other substrate materials. Notably,
- It doesn't compact (like sand)
- It is lighter than aquarium gravel
- It has a high cation exchange capacity (CEC)²
As soon as the Vivarium was completed I put in the fish (about 10 pair). Time to
kick back and relax.
I had effectively reduced my work load to feeding and making occasional water changes. I feed the fish mostly live brine shrimp, fruit flies,
mosquito larvae (when available), and less frequently frozen food and flake.
are not picky eaters. Indeed, they act more
like sharks in a feeding frenzy. I observed one male feed on a 1/2 inch cricket that
was trying to escape from a hungry frog (Phylobates vittatus
As time went by, my fish population increased to where I now have about 30 to
40 adult fish in this tank. I have never seen a juvenile, ever. The population
has stabilized at this level. I've seen no noticeable increase in adult fish over the past 12 months.
There are no mops in the tank. I do not pick eggs. There are, however, lots of
hiding places and plant roots. I had always assumed that would be the place they would
lay their eggs, and perhaps they do. One morning, however, I have noticed one pair
plowing into the substrate in a nice open area at the front of the tank. My first reaction, was
"Boy, that's stupid. Those eggs will get eaten in a second."
It never dawned on me to try and harvest them. Anyway, my regular water change
routine includes siphoning water into a bucket with a ®Python. Generally,
I toss the water on some bamboo that grows right outside my back door. But, one day
I needed some water to top off the daphnia tank outside.
I never gave it a thought. Several weeks later while harvesting some
daphnia, I though I saw a fish. Sure enough, there were juvenile F. nigeranius
swimming around. Remarkable since the water temperature fluctuates radically
(it's in partial sun on concrete in Phoenix, Arizona). We had already reached
100 degrees Fahrenheit!
Positive I had discovered the easiest way possible to raise large numbers of nigeranius,
I hurriedly e-mailed Bill Gallagher. Here is Bill's response:
"This is a variation of an old trick. One of the very finest breeders, Rosario LaCorte,
uses the "gravel" method almost exclusively for Fundulopanchax, instead of peat or
mops. He uses standard aquarium gravel (perhaps a little larger), they lay the eggs
into the gravel, then every couple of weeks you swirl the gravel around. The eggs,
being lighter, don't settle as fast, and if you swirl them in a circle, they gather
in a small area at the bottom of the water column, just above the gravel, in the
middle, and you can just put a standard net through that area and net out the eggs
from the tank. Messy, but it works for Rosario. Not sure what he does then, either
just water incubates the eggs or perhaps puts them damp peat moss, I think the
former. I would be worried about abrasion of the eggs, but I know Rosario is the
best, so it probably works."
What can I say. I was instantly deflated. Independent invention gathers few kudos especially
when you're not first. Regardless, I'm satisfied with this method. If
it works for Rosario and myself (wink), it could work for you too.
Turface comes in 50 lb. bags for about $8 to $12 (U.S.). Check with your local baseball
club or golf course for their supplier. Be sure to rinse it thoroughly to remove dust.
Soils with a high CEC tend to hold onto positively charged
nutrients (e.g., potassium (K+), ammonium (NH4+), etc.) better than soils with a low CEC. That is good for getting nutrients
out of the water column and to roots of your aquatic plants.
© 2002 Bill Edwards