Captive Care Notes: Flagfin Shiners (Pteronotropis, Family Cyprinidae)
Compared to minnows from more northern climes, Pteronotropis are fairly easy to keep. They can withstand warmer temperatures than most other U.S. minnows, and as such are one of the few local fishes than can be mixed with tropicals (although purists would cringe at the thought!). Pteronotropis are peaceful with other fishes of the same size and temperament and readily accept standard aquarium fare. Males usually color up during the spawning season, but unless you coax them to spawn and successfully raise their eggs, you will only get to see their beautiful battle dress once, maybe twice if you're lucky, before they expire. Propagating these minnows, or receiving captive-born progeny from other aquarists, is far more preferable than continually raiding their ever-declining habitat.
Bluenose Shiner, Pteronotropis welaka
A fairly recent (1999) discovery concerning the Bluenose Shiner is that it's a nest associate of Longear Sunfish (Lepomis megalotis). Nest association occurs when fish of one species (the associate) spawn in a nest guarded by a breeding male of another species (the host). The $64,000 question facing aquarists who wish to raise Bluenose Shiners is: Are they obligate or facultative sunfish nest associates? This is a biologist's way of describing whether a certain life history trait is biologically essential for survival (obligate) or just something that occurs under some environmental conditions but not others (facultative). In other words, do Bluenose Shiners need sunfish nests (or reasonable facsimiles thereof) to breed in captivity? Based on the few reports of captive spawnings available, probably not. In fact, evidence collected from other nest-associating minnows indicate that maybe it's not the nest that gets Bluenose Shiners "in the mood," but the odor of sunfish milt and ovarian fluid.
One of the first (if not the first) reported spawnings of P. welaka was published in an early issue of American Currents. Anthony Terceira (1975) reports placing two pairs of P. welaka into a 15-gallon aquarium with "natural gravel," a thick cover of water sprite, and one corner densely planted with foxtail. An airstone was "bubbling at a rather fast rate in the middle of the tank to provide maximum circulation of the water." Within two weeks the shiners had spawned and "scattered their eggs throughout the dense cover...". Although it's possible that Terceira's shiners spawned in the plants, it's also possible they spawned over the gravel and that the eggs were disbursed into the dense cover by the "rather fast" bubbling of the airstone. Terceira removed the parents and raised the fry on infusoria. After six days they became free-swimming and were fed paramecium and newly hatched brine shrimp.
Granier (1998) reports P. welaka "scattering eggs all over the substrate of the tank." Tank conditions emulated those in the wild -- soft water, pH 6.4 to 7.0, water temperature 10-25.5C (50-78F) -- and live foods help get adults into spawning condition. Not reported in that article are two potentially significant observations: Immediately after spawning the shiners assumed a nose-down position and quickly ate their eggs, and attempts to spawn them in bare-bottom tanks failed (B.G. Granier, pers. comm.).
The most detailed protocol for spawning the species comes from the book American Aquarium Fishes. Place 10-15 individuals into a 29-gallon tank with slight current, plants (or some other structure) around the sides, and an open middle area covered with coarse gravel or pebbles. Feed the fish on live foods for eight weeks, then lower the temperature to 18C (65F). Move the females to another aquarium and continue to feed them live foods. After another eight weeks of conditioning, return the females to the tank with the males and slightly reduce the current. Spawning should take place within a few hours. Turn off filters since the eggs are easily scattered into the current and drift throughout the tank. Remove the parents and begin conditioning them for several more rounds of spawning. Eggs hatch in 2-4 days, depending on the temperature. Eggs may also be collected in spawning mops or pebble- or marble-filled spawning trays for hatching in separate nursery aquaria. Keep turbulence to a minimum as it interferes with feeding. Feed the fry rotifers, infusoria, and green water; switch to daphnia and ostracods after two weeks. Brine shrimp nauplii are not readily accepted.
Bluehead Shiner, Pteronotropis hubbsi
The Bluehead Shiner's spawning behavior can be seen in the aquarium by following the same protocol described for the Bluenose Shiner above. Outdoor spawning is also possible. Aquarist David M. Schleser (pers. comm.) reports spawning Bluehead Shiners in 800-gallon, bare-bottomed fiberglass ponds each stocked with a pair of Pumpkinseed (Lepomis gibbosus). In previous years, Bluehead Shiners placed into ponds without sunfish colored up but did not spawn. In laboratory studies, Fletcher and Burr (1992) raised P. hubbsi larvae on plankton collected from a pond.
The Flagfin Shiner, Pteronotropis signipinnis
Several aquarists report success breeding the Flagfin Shiner. Albanese (2000) placed 2-4 adults of unknown sex into each of four 10-gallon aquaria containing water from the Mississippi stream where they had been caught, sand-gravel substrate, and a few plants. The shiners were fed stream invertebrates, frozen bloodworms, and flake food. Imitating seasonal changes in stream conditions, the temperature was gradually raised from 17C to 22C (63F to 72F) over the course of a month. Lights were on for 10 hours a day. Prespawning behavior consisted of the male chasing the female and nudging his head against her abdomen, usually near the vent. The female responded by fleeing. Sometimes the male quivered when he got close to his potential mate, shuddering his body from side to side while swimming. Spawning always occurred along one of the sides or in the corner of the aquarium. During spawning the male wrapped his caudal fin around the female's body near her anal fin. Eggs were released all at once and quickly sank. Several times both parents consumed almost all of the eggs before they hit the bottom. Pairs produced multiple clutches, with at least four days between spawnings.
Stober (1977) spawned P. signipinnis in soft, slightly acid (6.5-7.0 pH) water. Tabb (2004) reported success at 7.0 pH with a hardness of 6 or 7. In fact, Tabb suggested that lowering the hardness through partial water changes -- 1/6 daily using distilled water -- may be an important spawning cue in that it simulates the drop of hardness that occurs in the wild after spring rains. Tabb spawned his flagfins in a 30-gallon aquarium designed to simulate both the runs and pools found in flagfin habitat. The left side of the tank, where the filter was located, was unplanted and lit (the run); the right was dark and planted with Anacharis (the pool). The filter outflow was directed straight across the back wall of the tank, about halfway down from the top. A leaching piece of driftwood was used to add tannins to the water (blackwater extract should also work). The flagfins -- two males and five females -- spawned at the front of the tank (similar to that reported by Albanese), away from the current. Like Albanese, Tabb conditioned his fishes on live food, and gradually increased temperature and photo-period to simulate the onset of spring. Tabb started at 15.5C (60F) and began increasing the light by 15 minutes a day until the tank was lit for 11 hours daily. Then he raised water temperature a degree a day until water temperature reached 23C (73F), when spawning began. Fry took green water and aufwuchs scraped from the leaves of pond plants.
"Flagfins are breeding machines," wrote Bob Muller, the chairman of NANFA's Breeder's Award Program (2003). Muller's initial success with the species began when he placed seven wild-caught males and three females into a 15-gallon tank. When he raised the water temperature from 17C (62F) to 22C (72F), the flagfins started spawning -- over gravel placed underneath the outflow of a Whisper power filter -- and never stopped as long as a temperature of 22-24.5C (72-76F) was maintained. Eggs hatched in three days at 24C (75F). Fry ate green water until they were free-swimming, at which time they began eating APR (artificial protozoa and rotifer). After a week the fry took brine shrimp nauplii.
The Sailfin Shiner Complex, Pteronotropis cf. hypselopterus
Like Flagfin Shiner, Sailfin Shiner will reach spawning condition on traditional aquarium fare. Stober (1975) reports placing one male and two females into a 20-liter aquarium with soft (25 ppm), alkaline (pH 8.2) water kept at 24C (76F). Spawning occurred several weeks later. Eggs appeared to be semi-adhesive; most were scattered all over the gravel, some in the plants. Hatching took place in three days. The parents ate some of the fry.
The Broadstripe Shiner, Pteronotropis euryzonus
Katula (1993) reported getting Broadstripe Shiner into breeding condition on flake food alone with the following protocol: Separate males and females for several weeks in 5- to 20-gallon aquariums with moderate water flow and a pH of 7.0-7.8. Add the males after making a 25% water change, slowly raising the temperature to 25.5C (78F). Provide spawning mops or thick java moss to catch the eggs and to help prevent the parents from eating them. If moving eggs to a nursery tank, be sure to only use water from the spawning tank. Eggs hatch in 5-7 days. According to Katula, fry blend in with their surroundings, and attach themselves to vertical surfaces, presumably by elastic glue from pores located on their heads, as described for P. hypselopterus above. After five days the fry began swimming on their own, and started feeding on infusoria or microworms. At 10 days of age, they're big enough to eat newly hatched brine shrimp. Females become sexually mature in six months, males in eight.