Lucania goodei, the Blue Fin Killifish

Photo: A group of Lucania goodei, the bluefin killifish, in a sorting jar.

 

While collecting fish in Coleto Creek in Victoria County, Texas (I’ll be blogging about this collecting trip shortly) with our nephew (Darin), his wife (Anne), and three-year-old daughter (Sylvie), Darin picked a fish out of the seine net and asked me what it was. I was stumped. It was obviously a killifish, but one I’d never seen before. We caught and retained several of both sexes.

The photo at the top as well as the one below was taken in one of our greenhouses in a jar we use for sorting. The quality is bad, but I’ll try for better photos later.

Back at home, both Darin and I did some online research trying to identify the fish. I went through all the Fundulus species and found nothing. Then Darin texted me, “Lucania?” Sure enough, Lucania goodei, the bluefin killifish has been introduced into Texas. A bit of research found this species is native to southeastern United States, but has been introduced into California, North Carolina, South Carolina, and Texas (Gallaway et al. 2008; Hubbs et al. 2008). According to Gallaway, in Texas it was established in a small artificial wetland in Victoria, Texas. Victoria is on the banks of the Guadalupe River and Coleto Creek is one of its tributaries. The US Geological Survey map (see: https://nas.er.usgs.gov/queries/FactSheet.aspx?SpeciesID=696) below shows this introduction; see the southern most brown blotch, that is part of the Guadalupe River and Coleto Creek. For a video time lapse of this species occurrence in Texas, go to: http://www.fishesoftexas.org/taxa/lucania-goodei below the USGS map.

 

I also discovered during the research that another Lucania, L. parva, is native to the Texas coast. But, it doesn’t look anything like the fish we caught.

According to www.fishesoftexas.org, the species’ habitat is “Heavily vegetated ponds and streams, in areas of little or no current (Gilbert and Burgess 1980). Frequently associated with spring habitats, and may occur in waters of moderate salinities (up to 10.3 ppt; Kilby 1955; Gilbert and Burgess 1980). Species may occur in waters of extremely low dissolved oxygen content, where it apparently uses small, upturned mouth to obtain oxygen from thin surface film as does Gambusia affinis (Lewis 1970; Gilbert and Burgess 1980).”

Keeping and Breeding

From what I can glean from various sources, this species should breed year around in captivity. I plan on setting them up for breeding shortly and will raise them the same as we raise Fundulus chrysotus.

For the hobbyist, here’s what Aquahobby has to say about this fish:

“The bluefin killifish are sexable when they are mature. The males have bright blue marks on the dorsal fins, whereas the females only clear dorsal and anal fins with no color at all. The males also have red or yellow marks on caudal and anal fins and are larger and more slender than females, which are smaller but plumper. Bluefin killies are onmivores, meaning they eat both animal and plant matter. Bluefins prefer munching on inverts such as mosquito larva, snails, scuds etc. Bluefins also will pick on the algae on aquatic plants. Best food for them is frozen bloodworms, especially for the wild caught and pond/tub bred ones that are picky eaters, refusing to consume flakes. Breeding is actually easy, as long as you have lots of plants such as Java moss or use a spawning mop, and feed them live/frozen foods.

“The bluefin killifish do better in heavily planted tanks than bare tank or not enough plants. They will behave naturally in the planted tank which is why I always have to add Java moss, banana plants and elodea to my bluefin killifish tank. They are better in a species tank, as they can be shy or playful depending on the tankmates. Dwarf livebearers (Heterandria formosa) and Japanese Rice fish (Oryzias latipes) are my bluefin killies’ tank mates, all of them in a 115 L tank without a heater. Bluefins tolerate up to 26°C but they do better at lower temperatures. I always put the bluefins in my 470 L tub outside with duckweed and elodea during the summer. I always get some fry in the fall when I fish the bluefins out of the tub. The bluefins can breed in the tank as long as you can provide the fry with green water, then later newly hatched brine shrimp. Make sure the parents are removed from the tank if you want babies, as the parents will eat the eggs and the fry. Bluefins are my favorite native killifish because they have playful personalities and are very easy to take care of.”

And here’s what the Chicago Zoological Society says,

“Bluefin killifish are elongated and minnow-shaped with a laterally compressed body. They are sexually dimorphic (have two distinct gender forms); males are longer than females and have blue markings on the anal and dorsal fins. Males have a bright blue, black-edged dorsal fin, which is green at the front base and deep orange-red at the rear base. They contain more blue than females and have an orange caudal (tail) fin, the base of which fades to yellow. Their pelvic fins are orange and edged in black. Females have clear fins. Bluefin killifish have a strongly upturned mouth and convex tail. The overall body color is brown/grayish-white. A dark band runs from the snout, extends through the eye, and ends where the tail fin is attached. Body color above this band is a lighter brown with subtle green highlights at times appearing a hazel color. The underside is a paler brown.

“Bluefin killifish live in freshwater and brackish water habitats. They are found in shallow, heavily vegetated areas with little or no current, such as ponds, lakes, pools, and backwater streams. Bluefin killifish are diurnal (active during the day). They will school at times. Males will establish territories, but will not become overly aggressive.

“The reproductive peak for bluefin killifish is from March to mid-summer. Over a period of several weeks, spawning (egg fertilizing/laying) pairs deposit up to 20 individually released eggs per day on vegetation, algae, stones, or a sand substrate. They lay their eggs in areas of dense vegetation.The eggs are fertilized externally. Adults will not guard the eggs, which hatch in about 12 days.

“Young bluefin killifish eat small shrimp, worms, and other small invertebrates. They can be sexed after about three months.

The bluefin killifish feeds on small insects, crustaceans, and plant material.”

You should be able to glean enough husbandry information from the above two sources to be successful with Lucania goodei.

Taxonomy

According to https://itis.gov/, the authority we use to determine the validity of scientific names (since you must pick one source, or you bounce all over the place about taxonomy), the genus Lucania (Girard, 1859 – bright fin killifishes) has three valid species:

Lucania goodei (Jordan, 1880)
Lucania interioris (Hubbs and Miller, 1965)
Lucania parva (Baird and Girard in Girard, 1855)

Lucania interioris is from Mexico. As mentioned above, L. parva is found naturally in Texas, but in decades of collecting I’ve never seen it.

Almost every collecting trip I go on has its surprises. Lucania goodei is one, but not the only one, for this trip. You’ll have to read my next blog to find out what other surprise occurred.

 

References:

Gallaway, B.J., R.G. Fechhelm, and R.G. Howells. 2008. Introduction of the bluefin killifish (Lucania goodei) in Texas. Texas Journal of Science 60(1):69-72.

Gilbert, C.R., and G.H. Burgess. 1980. Lucania goodei (Jordan), Bluefin killifish. pp. 534 in D. S. Lee et al., Atlas of North American Freshwater Fishes. N. C. State Mus. Nat. Hist., Raleigh, i-r+854 pp.