In Our Own Backyards … Fundulus cingulatus
Many aquarists despair when it comes to keeping killifish native to the United States, since many species tend to be rather dull in coloration and uninteresting in either reproductive behavior or personality.
However, Fundulus cingulatus is hardly one of those ordinary brown fishes. F. cingulatus is a moderately sized killifish, with a maximum size of about 3 inches and a shape similar to the more familiar F. chrysotus. Male F. cingulatus are slightly reddish with bright, lemonade pink fins; the tail may have a gray border. In subdued lighting the unpaired fins may take on a deep rosy hue, and horizontal rows of red dots are noticeable along the sides. The eyes of the male reflect a blue sheen, and have an hourglass shaped pupil, a clear indicator of sex. Females are pale in comparison, and show a slight vertical bar along their flanks; they look much like female F. cyrosotus, but without the glittery spots on the sides. Females also tend to show a fleshy area at the leading edge of the anal fin.
These fish, which have become rarer in recent years, are usually found in tidepools along the lower parts of streams and in sluggish, lowland creeks. The species seems to be tolerant of brackish water, but prefers fresh water with just a bit of salinity. It has often been found in areas where red algae thrives, which may partially explain the distinctive coloration of the males.
An Active, Friendly Fish
This species is an upper-level, active chaser that requires plenty of swimming room. Bob McDonnel kept them in a 29 gallon tank that had housed Jordanella floridae. The water was moderately soft, warm (27C/80F), with slightly raised salinity (about 1 tsp. of Instant Ocean marine mix per gallon). The decor was simple, consisting primarily of rocks, driftwood and both live and artificial plants. The fish fed readily, willingly taking flakes and any other foods that were offered. Regular water changes and the presence of Malayan Livebearing Snails maintained water quality in the sparsely populated tank The fish tended to be active all the time, were not startled by viewer scrutiny, and enthusiastically greeted the aquarist at feeding time.
Propagation was fairly straightforward. Chasing and courtship were evident in the large tank early on; actual spawning was accomplished in a 2 gallon drum bowl nearly filled with yarn mops and several quarts of water from the main tank.
A single pair of conditioned fish were placed together and left for 4 to 7 days, being fed only live foods (to maintain cleanliness) and a little green water. On the eighth day the pair (still compatible and vigorous) were returned to the main tank.
The eggs were relatively large and developed well at the slightly lower temperature of the bowl (74F). After approximately two weeks they began to hatch, and java moss was added to the spawning container.
The fry were fairly easy to rear although they grew fairly slowly for the first few days. They actively took brine shrimp nauplii and other small food items, including green water, vinegar eels, and commercial baby fish food formulations. A pond snail was added to boost infusoria and to eat unconsumed material. A 50% water change was done every other day.
— G. C. K. A. Newsletter, July 1998