HAWAU-T-99-002 C2 LOAr c

Spawning and Production of the Lemon Hyphessobryconpalchripinnis

Brian Cole, M.S., Paul Kotal, M.S. and Michael Haring, B.S. Sea Grant Extension Service School of Ocean and Earth Science and Technology

February 1999

Center for Tropical and Subtropical Aquaculture Publication Number 142 ACKNOWLEDGMENTS

The authorswish to extenda sincerethank you to all who contributedto the completionof this manual,including Alcian Clegg and Jean McAuliffe of theCenter for Tropicaland Subtropical Aquaculturefor layoutand editing, and Diane Nakashima of theUniversity of HawaiiSea Grant CommunicationsOffice for printingadvice and assistance. The production of this fact sheetis the combined effort of three institutions.

1! TheUnited States Department of AgricultureCenter for Tropicaland Subtropical Aquaculture CTSA!through a grant&am the U.S. Department of Ayiculture Cooperative State Research, Educationand ExtensionService USDA grants¹96-38500-2743 and ¹97-38500-4042!.

2! TheUniversity of HawaiiSea Grant Extension Service SGES! through the National Oceanic and AtmosphericAdministration NOAA!, project ¹ A/AS-1,which is sponsoredby theUniversity of HawaiiSea Grant College Program, School of OceanEarth Science and Technology SOEST!, underInstitutional Grant No.NA86RG0041 &om NOAA Office of SeaGrant, Department of Commerce, UNIHI-SEAG1VLNT-TR-99-04.

3! TheAquaculture Development Program, Department of Agriculture, State of Hawaii,as part of theAquaculture Extension Project with theUniversity of HawaiiSea Grant Extension Contract ¹ 44576.

Theviews expressed herein are those of theauthors and do not necessarilyreflect the views of the funding agenciesor their sub-agencies.

SEA GRANT Table of Contents

INTRODUCTION

TAXONOMY

MORPHOLOGY .

DISTRIBUTION .

WATER QUALITY

REPRODUCTIVE BIOLOGY .

GROWTH

LITERATURE CITED. INTRODUCTIO'N

Whilemore than 60 speciesin thegenus Hyphessobrycoii have bccn identified, very few areavai l ableon theornamental market despite their popularity Baensch1993!,Hyphessobrycov pu chripi nnis !is just oneof manyfish in thegroup of tetrasor moreaccurately, Characins, traded in theornamental industry.Lemon tetras are peaceful and nonaggressive to other anddo well incommunitytanks. Like manyof theother tetras, they can be considered a schoolingfish anddo betterin groupsof five to twenty individuals.

AlthoughLemon tetras are fairly easyto spawn,they are not as colorful as many of thc othertctras and are not widely spawnedor importedin largequantitics for economicreasons Axelrod and Schultz 1983!. As of 1992,the Lemontetra was listed as number 69 in the]ist af top 100fish importedinto theUnited States with just over5,300 imparted per month Chapmanet al. 1997!.Thc historical estimated farm gateprices producerscould expect for a groupof variousone-inch Hyphexvobrycon sp. are summarized in Figurc 1. Theseprices were taken from a seriesof priceJists published every five yearsby oneAsian trans-shipper. A one-inchfish wasused to serveas an easy reference point, although many can be sold at smallersizes. The Lemon tetra could be consideredwhat the industry refers to as a "breadand butter" item.

Estimated Farm Gate Prices

0.18

0.16

0.14

0 0.12 8 0.1 Co 0.08 D 0.06

0.04 0.021980 1985 1990 1995

Year Figure l. Estimated average farm gale prices for selcctcdone-inch Hyphessohryconsp. TheLemon tctras, un1ike many tropical fish traded onthe ornamental market, have not gone through reclassifieationsandnumerous name changes ashave others, This fish was occasionally called ervthrophthalni usbut is not valid scientifically Axelrod etal. 1977!. J.Gery discovered thatthe generic name for the more common was possibly incorrect but since it was in such common usagehedid not assign a new one and suggested thata reviewofall South American Tetragonopteri nae beundertaken, Todate this review has not occurred. TheGenus wasestablished in 1908 byDurbin Baensch 1993!. Todate, thctaxonomic classification remains; Family: Characi dae,Subfamily: Tetragonopterinae,: Dyphessobrycon, Species: pulchripinnis,

MORPHOLOGY

Hyphessobryconpulchripi nnis are not as colorful as many of the other Characins unless well maintained andgiven feeds with the proper level ofavailable carotenoids toenhance andmaintain theircolor. They do makeanexcellent contrast fishdue to the bright yellow color and the bright red upper part of the eye. As showninFigure 3,mature adults are fairly easy toscx. The females have a deeperbodycontour andthe blackedge ofthe anal fin inthe males ismore pronounced thanin the females. Fully grown Lemon tetras arefrom three tofive centimeters cm!in length with a fivecm speciinen beingunusually large.

Figurc3. Photographof Hyphessobry conpulchripinnis male top! andfemale bottom!. DISTRIBUTION

Distributionis throughout Figure 2! exceptthe southern part and arid Pacific slope of Chile Axelrodand Schultz 1983!. The native habitat comprises the small tributaries of thelower Amazon basin, primarilybrooks emptying into the Rio Curua do Sol and the lower and rniddle Rio Tapajoz between Itaitubaand Jacare Acanga Gery 1980!,

Figure2. Naturaldistribution of Hyphessobrycon pulchripinnis. Modified from Baensch1991!,

WATER QIJALlTY

Properwater quality is oneof themost important aspects for successin spawningCharacidae. Most prefer softand acidic waters. Table 1 providesthe ranges in waterchemistry considered acceptable for theproduc- tion of Hypjiessobryconpulchripiniiis,

Table1 .Ranges in importantwater quality parameters for thereproduction of Lemontetras. Waterchemistry can vary greatly in Hawaiidue to thewide range of environmentaland geological condi- tions encounteredthere. While water sourcesthat fit within theseparameters can be found in the State,in somecases, the water chemistry may have to bealtered to successfullybreed some fish. For many tetras, hardnessand pH are the inost important parametersto consider.Hardness is the total concentrationof alkalineearth ions expressed asan equivalent calcium carbonate CaCO,! in mi1 ligramsper liter mg/L!, with theprincipal components being calcium and magnesium carbonate or sulfate.Hard water contains high concentrations of alkaline earth ions while soA water has low concentrations. Other ions contribute to hardnessbut are usually present in suchminute quantities that their effect is minimal.Hardness is usually expressedas temporary or carbonatehardness and permanentor non-carbonatehardness. The sum of thesetwo components istotal hardness and is usually expressed asmg/L CaCO, Boyd 1979!. The term "temporaryhardness" is commonlyused because carbonate hardness can be removed by precipitatingthe calcium andmagnesium cations or saltsby boiling.

The most common method to reduce hardness is to dilute the hard water with distilled water. Other means includeuse of a cornrnercialwater softener such as reverse osmosis units or ion exchangegel filters if large quantitiesof soA water are needed,

ThepH is a measurementof a water'sacidicity and indicates a changefrom a neutralpH of 7,0,Neutral watercontains an equal balance of hydrogenions and hydroxide ions. A higherproportion of hydrogenions resultsin a moreacidic water lowerpH! while a higherproportion ofhydroxide ions results in a more alkalinewater higher pH!. I fsmall quantities of waterare needed, reduction of pH is generallya simple matterand can be achieved through peat filtration. If largequantities of waterare needed, a stronginorganic acidsuck as phosphoric, sul furic, or dilutedhydrochloric muriatic! can be used to reducepH. Thereare alsocommercially available compounds sold through retail pet stores in theform of solidtablets, granules or liquid drops.

When using a strongacid to reducethe p H,be sureto run severaltests to determinehow much acid is requiredto reducethe pH of a givenamount of waterto thedesired level. When handling strong acids, reviewand observe all safetyprecautions to preventaccidental spills or exposureto eyesand skin.

REPRODUCTIVE BIOLOGY

Many speciesof fish produceeggs only oncea yearwhile someothers produce eggs repeatedly over thecourse of a spawningseason. Lemon tetras fall into thelatter category. Female Lemon tetras will ovulate on averageabout once every four days as shown in Figure 4 Burt et al,1988, Nakatsuru and Krarner 1982!.During each ovulation, a femalewill spawnan average of 23 timesproducing an average total of 160 eggs.Ovulated eggs are sinking and slightly adhesivewith diametersof 0.74 mm that swell to 0.90 mrn aAer waterhardening. Spawning is promiscuousand males will spawnevery day that receptive females are available Nakatsuruand Kramer 1982!. Fertile eggs hatch in about24 hoursand there is no parentalcare given to the eggsor fry. Thismay lead many aquacuIturists tobelieve that there may be an unlimited ability for males to fertilize eggs. However,Nakatsuru and Kramer found that there may indeed be a limitationto themales' ability to fertilize eggs.The percentage of developing eggs declines as a functionof thenumber of spawningacts by themale. Thedecline is most easily explained by a reductionin the quantity or quality of spermreleased atsuccessive spawnings Nakatsuru and Kramer 1982!.

Ovulation Intervals

30

25

20

I5

I 0 I 2 34 5 6 78 910 I l Interval Length in Days Figure4. Percentdistribution of'ovulations since previous ovulation for Hyphessobrycon pulchripinnisunder controlled conditions n=245!. Modifiedfrom A. Burt. 1988!

Therate of externalfertilization is maximizedonly at sperinconcentrations of 1,000,000sperm per milliliter Nakatsuruand Kramer 1982!. After ten spawning acts, male reproduction is limited by spermsupply. AAer20 spawning acts in a oneto onesex ratio, reproductive success could be enhanced by restoring the fertilizationrate rather than by gaining additional spawning. AAer 30 spawning acts, reproductive success is limitedalmost entirely by fertilization rate. I ffemales are not limited, males could be expected to fertilize about136 eggs per day, an almost identical number to the number of ovulatedeggs produced by a fernale everyfour days Nakatsuruand Kramer 1982!.

Lemontetras are egg scattering spawners like inany of theother Tetra sp. and Barb sp. Usually either pairs or groupsof broodstock, with one male to fouror fivefemales, are set up in tanksthat arc no larger than tengallons and as smal I asthree gallons. This ensures that there is at least one fernale ready to spawn. Pairs canbe used but the percentage of tanks that contain eggs aAer the spawning run will bereduced. A sub- strateofbrushes, nylon yarn, fine strips of plastictied to a baseor fineplastic grass is placedinto thc tank by itselfor ontop of anegg collector. Egg collectors should be constructed to fit thetank edges snugly so thatthe brood stock does not hidein anycrevices. Collectors should have a minirr.umdepth of aboutonc inch,although deeper collectors work very well. It shouldbe covered with a screenlarge enough to letthc eggssink through but small enough to keepthe brood stock out. The use of collectorsalso allows thc movingand consolidation of the eggs so that the spawning tank is not used for larval rearing and dcv8op- mentand can be set up immediatelyfor anotherspawning run. For spawning,three- to five-gallontanks are adequate and ten-gallon tanks would be the largest that is practical.The larger the tank the greater the chances of theeggs being scattered throughout thc tankmaking it morediNicult to collect and consolidate the eggs for larvalrearing. The pairs or groupsare placed into the tankusually in theaAernoon. Spawning wi 1 occur1 the following morning and will startat sunriseand last two to threehours. AAer spawning is complete,the brood stock or eggcollector is reinovedto preventcanni- balism of the eggs.

Eggswi I 1hatch in 24 hoursand in aboutfive daysfry becomefree-swimming and able to takea firstfeed of infusoria or a commercialmicro diet of 50 microns or less,although somesuccess has been achieved with live freshwaterzooplankton. By theeighth day, fry will takenewly hatched brine shrimp and by dayten to twelvethe fry arelarge enough to moveinto a growout tankor pond.The fry canthen be weaned onto a commercialproduction diet startingwith a finepowdered swim-up or starterdiet.

GROWTH

Lemontetras were stocked in anabove ground tank, six feetin diameter,at a densityof 1.9per gallon ,5 perliter!. Fishwere weaned for thefirst two weeksusing a combinationof live brineshrimp and a fine powderedcommercial trout swim-up diet containing55% crude protein, 16% crude fat, 3% crudefiber, 1 2%ash, and 1%phosphorus. After theinitial two-weekweaning period, the fish werefed to satiationonce daily,strictly on the commercial diet. During thc growout period Augustthrough rnid-November! tempera- tureswerc in theoptimum range for thefirst 60days of thetrial andthen began falling under the optimum rangefor the last 60 days as shown in Figure 6.

28

26

24 i' CL 22 I 20

3/22 4/22 5/21 6/20 7/20 8/19 9/18 10/18 11/17

Figure6. Temperaturerange at WindwardCommunity College during the spawningand grow outperiod for Hyphessobryconpulchripinnis.

LITERATURE CITED

Axelrod,H.R. andL.P. Schultz. 1983.Handbook of TropicalAquarium .T.F.H. publications, Inc, Ltd. Neptune City, NJ

Axelrod,H.R., C. W. Emmens,D. Sculthorpe,W. Vorderwinkler,N. Pronekand W.E Burgess. 1977. Exotic Tropical Fishes. T.F.H. Publications,Inc. Ltd. NeptuneCity, NJ

Baensch,H.A. and Dr. R. Riehl, 1993. Atlas Vol; 1-2. Mergus-VerlagGmbH HansA.

Boyd,C.E. 1979.Water Quality in WarmwaterFish Ponds. Craftmaster Printers, Inc. Opelika,Alabama,

Burt,A,, D.L. Kramer,K. Nakatsuruand C. Spry.1988. The tempo of reproductionin Hyphenobrycon puichripinms !,with a discussionon the biology of"multiple spawning" in fishes.Envir. Bio. of Fishes 2! 15-27.

Chapman,F.A S, Fitz-Choy, E. Thurnberg and C.M. Adams, 1997. United StatesOf America Trade in Ornamental Fish. J. World, Aqua. Soc. 28!:1-10.

Gery,J. 1980.Rediscovery of theLemon Tetra HyphessobrJ con pulchripinnis. Trop. Fish. Hobbyist July! 35-38.

Nakatsuru,K. andD.L. Kramer.1982. Is SpermCheap? Limited Male Fertility andFemale Choice in the Lemon Tetra Pisces,Characidae!. Science 16! 753-754.

Rundle,J. 1994.Breeding the LemonTetra. Breeding Tropical Fish. June1994.

Scheurmann,I. 1990.Aquarium Fish Breeding. Baron's EducationalSeries Inc. Hauppauge,N.Y.

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