Blackwater Aquariums: How to Setup a Biotope Tank

Discus and angelfish thrive in a planted blackwater tank. Dwarf cichlids also do well in this type of aquarium. Skiptocontent fishtankadvisor Menu Ifyou’relookingforanewtypeofaquariumchallenge,Isuggestablackwateraquarium! Blackwater?Youmaybethinkingthisdoesn’tsoundlikeanattractiveaquarium.Maybeitsoundsalittlemysterious. Wanttoknowmore?I’llexplainwhatablackwateraquariumis,whyyouwantitandhowtosetoneup. InthisarticleWhatisblackwater?Whyisthewatersodark?Whatisablackwateraquarium?FishthatloveblackwateraquariumsHowtosetupablackwateraquariumpHandblackwateraquariumsFishhealthbonusMaintainingtheblackwateraquariumFinalthoughts Whatisblackwater? TheAmazonRiveranditstributariesareclassifiedaswhitewaterandblackwater. WhitewaterhabitatshaveaneutralpHaround7.0,thewatercarriessuspendedparticlesandplentyofnutrients.Thewhitewaterhabitatisrelativelyclear. Blackwaterhabitatshavedark-colored,transparentwatercausedbylargeamountsofdissolvedhumicsubstancesdissolvingintothewater.That’sbecausetheriversriseandextendintofloodplains.Ifthefloodplainhappenstobeaforestwithlotsofleaflitter,thewaterwillbecomeacidicandstainedbythedecomposingleaves,seeds,fruit,andwood. Thisnichehabitatiscalledigapóor“rootforest”inBrazil.Thetwistedtreerootsandhumicacidscreateauniquefreshwaterhabitatthat’shometoover200speciesoffish. Whyisthewatersodark? Wild-caughtgreenseverum Whenyoumixwaterwithlogs,twigs,andleavesthingsstarttodecay.Acombinationofbiological(bacteriaandfungi)andchemicalprocessesbeginbreakingdowntheorganicmatter.Humicsubstancescontainedintheplantmaterialarereleasedintothewater. Innature,humicsubstancesarenotjustonechemicalcompound.Thewatercontainsaliteral“soup”ofallkindsoforganiccompounds.Humicacidsaredarkbrowntoblackincolor.Fulvicacidsappearmoreyellowish. ThechemistryiscomplexbutallyouneedtoknowisthatthesenaturalcompoundstintthewaterandhelptolowerthepH. Whatisablackwateraquarium? TheideabehindblackwateraquariumsistosimulatethewaterchemistryofAmazonianblackwaterandhavephysicalcharacteristicsofthefloodplains.Thismeanstheaquariumwaterneedstobelowinmineralsandaquascapedwithliveaquaticplants,aquariumwood,andorganicmatter(leaves)thatwilldecompose. Overtimetheaquariumwillage,meaningthedecomposingplantmaterialwillreleasenaturalacidsandothercompounds,causingthewatertobecometea-colored. Ablackwateraquariumissimilartoaplantedaquarium.Themaintaskismaintainingahabitatfortheplantsalongwithacontrolleddecompositionofleaflitter. Acid-lovingfreshwaterfishareaddedtoprovidecolor,movement,andinteresttothebiotope.Thefishalsoaddnutrientsandcontributecarbondioxidefortheplants,creatingabalancedecosystem. Fishthatloveblackwateraquariums Bleedinghearttetras Whilealotoftheset-upsisfocusedonliveplantsandwaterchemistry,thefishthatthriveinablackwatertankaremany! Thereareover200speciesoffreshwaterfishthatinhabitnaturalblackwaterenvironments.You’llhaveplentytochoosefromforyourtank.Someofthesespeciescangrowquitelarge.Besuretodosomeresearchbeforeselectingthefish. Dwarfcichlid–Apistogrammamendezi Herearejustafewofthemorecommonfishthatwillthriveinablackwateraquarium: Tetras(cardinals,neons,andothers) Geophagus Bryconspecies Firemouthcichlids Discus Pimeloduscatfish Loricariidcatfish Uaru Gouramis Apistogramma. Mostaquaristschoosetogowithsmallerschoolingfishliketetrasandsomeinterestingcatfish.Discusandangelfishthriveinaplantedblackwatertank.Dwarfcichlidsalsodowellinthistypeofaquarium. Flagtailcorysalsothriveinablackwaterset-up Howtosetupablackwateraquarium Aquascapingisapersonalthing.Notwotanksarealikeintheirlayout.I’vecompiledmy“must-haves”basedonyearsofsettingupandmaintainingblackwateraquariums. Aquarium Sizedoesnotmatter.Youcanuseananotankorbuilda500-gallonriveraquarium! Substrate Afinegravel(notsand)workswelltoanchorplantsandprovidearootzone.ManyAmazonianfishliketosiftsandwhilelookingforlivefoods.Youcangowithalight-colorednaturalgraveloradarkerspecialtysubstrateforplantedaquariums. Lighting Beingunderaforestcanopytheblackwaterbiotopeissomewhatdimlylit.Ifyoudon’tplanonusingliveplantsalmostanykindofaquariumlightwillwork.Iliketouseawhitedaylight-styleLEDfixture.Itmakesiteasiertoseeintothetea-stainedtank. WhiteLEDalsocreateslightripplesthroughoutthetank,justlikesunlightpassingthroughtheforesttrees.Ifthefixturehastheabilitytoadjustthecolorspectrumyoucanexperimenttoseewhichcolorblendbringsoutthecolorsofyourfish.Manyaquaticplantswillgrowwellundermedium-brightnessLEDlightingtoo. Heater Asimplesubmersibleheaterwillstabilizethewatertemperatureinthe75-80°F(24-26.7°C)range. Water Thisisanimportantcomponentofablackwateraquarium.Thewatershouldbelowinhardness(GH)andalkalinity(KH).Theidealrangeisinthe2-5-degreerange. Ifyourtapwaterisharder,blendthehardwaterwithreverseosmosiswatertoachievethedesiredlevels.Itdoesnothavetobeexact.Youjustwantthehardnesstobelessthan8degrees.ThiswillbringthewaterchemistryclosertotheAmazonianconditionsandallowthepHtoslowlydropovertime. Watermovement Withasmalleraquarium,ahangontheback-powerfiltermayprovideallthewatermovementyouneed.Forlargertanks,acanisterfilterorpowerheadscanbeusedtocreateaflowofwaterthroughouttheaquarium. Ifyouareraisingliveplants,don’tagitatethewatersurfacetoomuch.Itwilldriveoffthecarbondioxideplantsneed.Iftherearenoplantsyoucanaeratethewaterasmuchasyoudesire. Filtration Isuggestusingmechanicalfiltermediatocapturedebris.Sponges,filtercartridges,andothertypesofmechanicalmediashouldbecleanedorreplacedmonthly.Activatedcarbonwillremovesomeofthehumicsubstances. Isuggestusingactivatedcarbonforonlyaweekorsoeachmonth.Thiswillremovesomeofthehumicsubstancesalongwithotherundesirableorganicsthatbuildupinthewater.Ifyourtankbecomestoodarkforyourliking,usemoreactivatedcarbonandchangeitweeklytoreducestainingofthewater. Driftwood UseanytypeofaquariumwoodthatissafeforthetankandisnotknowntoraisepH.Itprovidesanaturallookandgivesfishaplacetoexplore. Someaquariumwoodswillreleasetanninsintothewater.ManzanitawoodispH-neutralandlooksgreatinyouraquarium. Rocks Smoothstonesandroughrockcanbeusedtocreateariverbedorjaggedoutcropping.Youmustchooserocksthatwon’treleasecalcium(waterhardness)oralkalinity(carbonates). SomerockswillincreasethepHbyslowlyreleasingcarbonatehardness(KH)intothewater,soresearchbeforeyoupurchaserocks. LeafLitter Caremustbetakenwhenaddingleavestoyourtank.Youdon’twanttoaddjustanyleafyoufindontheground. Indianalmondleavesarereadilyavailableonlineandarecompletelysafe.Alderconesarealsousedtoincreasetannins.Aquaristsreportthesedriednativetreeleavesaresafeandeffectiveintheaquarium: Pedunculate–Quercusrobur Sessileoak–Q.petraea Turkeyoak–Q.cerris Redoak–Q.rubra Europeanbeech–Fagussylvatica Hawthorn–Crataegusmonogyna Japanesemaple–Acerpalmatum. Youmayfindpreparedliquid“blackwater”additives.Iamnotsureiftheseformulationshavethesamebenefitsofthenaturalhumicsubstancesgeneratedintheaquarium. Justbecauseaproductmakesyourtankbrowndoesnotmeanithasallthepropertiesofhumicandfulvicacids. Byallmeans,experimentandhavefun.ButIrecommendtryingnaturalplantmatterinadditiontopreparedliquids. HowmanyleavesdoIneed? Thereisnoscientificansweron“dosing”withleavesorcones.Sincetheyarenottoxicyoudon’thavetoworryabouthurtingthetank. Almondleaveshavebeenusedatarateoftwoleavesfor10-15gallons.Thedriedleavesmaytakeadayortwotosoakupenoughwatertosink.Replacethemevery30to60days.You’llhavetoexperimentandjudgeforyourself. Liveplants Youdon’tneedtohaveliveplantsifyou’rebuildingabiotopethatmimicsafast-movingstream,whereplantswouldn’tnormallygrow.Ifyoudochooseliveplants,selectmediumtolow-lighttypes. Anubias Cryptocoryne Javamoss Javafern Watersprite Taxiphyllum Iliketousealiquidfertilizercontainingironandothertraceelements.Iuseahalfdoseatfirstuntiltheplantsstartgrowingandneedtobepruned.Ifthegrowthrateissatisfactory,Icontinuewithahalfdose.Underbrightlighting,Iusethefulldose. Experimenttofindtherightdoseregimenforyouraquarium. pHandblackwateraquariums ThetopicofacidicpHandfreshwaterfishisfilledwithfactsandfiction. Innature,thepHofnaturalwaterscanfluctuatewildlyduringthecourseof24hours.InthemorningthepHcanstartoutat5,riseto9atnoonandfallbackto5intheevening.ThisnormalriseandfallinpHarenotstressfulorharmfultothefish. Inanaquariumwithlowalkalinity,itwillbenaturalforthepHtodeclineduetonaturalacidsreleasedthroughthebiologicalfilter.ThehumicacidswillhelptolowerpHbuttheyarenot“strong”acids.Theywon’tlowerthepHifyouralkalinityishigh.ItispossibletorunthetankbelowpH6. Ifyouarenotexperiencedwithaquariumwaterchemistryordon’twanttocloselymonitorKHandpHlevels,keepthepHaround6.5to7.0bybalancingthecarbonatehardnessintapwaterwithpHinyourtank. Ifyoureallyliketotestthewaterandmakesubtlechangesinwaterchemistry,youcanrunthetankwith1degreeofalkalinityandachieveapHaround5.Manytropicalfishcolorupinanacidicenvironment,providedtheyarefedabalanceddiet. I’veseendiseaseproblemsallbutdisappearunderacidicconditions.Aswe’llsee,thereissomesciencebehindthisobservation. Irecommendthesetestkitsforkeepinganeyeonyourwaterchemistry: Low-rangepHtestkit Waterhardness(GH&KH)testkit Ammonia&Nitrite(forperiodicmonitoringofbiologicalfiltration). Fishhealthbonus Thereisgrowingevidencethatcaptivefishexposedtohumicsubstancesremaininbetterhealthandhealquicklyallontheirown. Traditionalmedicationscannotbeusedwithfishintendedforhumanconsumption.Thiscancauseachallengeforaquaculturefishfarming. Aquacultureresearchersarefindingthatnaturalhumicsubstancespromotediseaseresistanceandhealingofdamagedfinsandskin.Thisappearstoconfirmwhatbetta-keepershavebeensayingaboutalmondleavesformanyyears.Captivefishstayhealthierinablackwaterenvironment. Maintainingtheblackwateraquarium Justlikeallaquariums,anAmazoniantankwillbenefitfromwaterchanges.Myblackwatertanksdon’thavealotoffishandIfeedcarefully.Thereisnotalotofsludgeinthegravelorbuild-upofalgae-promotingnutrientslikephosphate.Ichangeabout20%ofthewatereverythreeweeks. Ifthetankisgettingtoo“dark”I’llincreasetheamountofwaterchangeormakethemalittlemorefrequently.Ifthegravelneedscleaningalight“sweep”withagravelsiphonisallthat’sneeded. Finalthoughts Ablackwateraquariumisfunandprovidesachallengetobothnewandexperiencedaquarists.Thekeytosuccessistotakeyourtime.Allowthenaturalprocessestobreakdowntheleavesandreleaseallthebeneficialsubstancesintothewater. Mytropicalfishreallycolorup,revealingsubtlecolorpatternsandiridescentscalesthatyoujustdon’tseeinanormalfreshwatertank.Iencourageyoutosetupablackwatertankandseeforyourself! Ifyouhaveanyquestionsorcomments,pleasepostthembelow.   YouMayAlsoLike InstallingaProteinSkimmer:Tips&MistakestoAvoid 14MostEffective&PeacefulAlgaeEatingFishforYourPond RedZebraCichlidCare:Diet,AquariumSetup&Breeding OrandaGoldfishCare:Tank&PondSetup,Mates&FeedingGuide Sharethispost:ShareonFacebookShareonPinterestShareonReddit Comments: Hi,Isetupmyfirstblackwateraquariumyesterday,usingROwaterandaddedsomeremineralizingsalttobringGHto120ppm.Thetemperaturewas25degreesCelsius,Iaddedquitealotoftanninliquidtogetnicebrowncolourofwater.Iusedanestablishedmaturefilterfromanotherfishtank.Addedsomecatappaleaves.Driftwoodisonthereaswell.Alllookedgood,andIaddedthreeangelfishesthere.Stronggrownupspecies.Alllookedfinelastnight.TodayearlymorningIfoundtwoofthemdead,oneinshockalmostdead.Iquicklysavedthelastonebringingitbacktotheestablishedtank.Butwhy??CheckedthepH,itdropped,butnotasbad.Itwas6.1.Iamshockedmyself. Reply Iamsosorry!ThepHisnotreallythatlow.FishcanhandlepHchangeswithinnormalranges.Itisreallyimpossibleformetosaywhathappened.Itistooeasytosaythedriftwoodwas“bad”orsomethinglikethat.Withouttestingit,it’sjustawildguess.Ifallthenaturalmaterialsandliquidtanninwerefromreputablesuppliers,Iamnotsurewhathappened. Reply Heyihadasimilarincidents,it’snotreallythephbutthesuddenintroductionofleavesandwoodcancauseanammoniaspikeandthusimmediateactionmustbetakenlikeremovingsomeofthewoodorleavesandperhapsafewwaterchanges.Ihopethishelpsinthefuture Reply Greatguide,bestonei’vereadsofar!Imlookingtostartonablackwateraquariumfromscratch,soiwouldneedtocycle.Doicyclethetankasiwouldwithafreshwatertank?Notplanningonputtingmuchplants,maybeoneortwospecies.Howwouldthataffectthecycle? Reply HiNick!ABlackwateraquariumwillcyclelikeanyfreshwatertank.Don’tover-feedandkeepaneyeontheammoniaandnitritelevels.Oncethey’vedroppedtozeroyoucanaddafewmorefish. Reply ThisisanEXCELLENTARTICLEforintroducinghobbyiststoBlackwaterhusbandry…Thevideoisperfectforthestory…Thankyouforpostingthis… Reply ThankyouJon!I’msogladyouenjoyedit! Reply Excellentarticle.ThankYou. Inmyexperienceoverthelast4to5years,humiccompoundsfromdecayingorganicslikeleavesarequitedifferenttoTanninsthatcomefromdeadrootsandbranches. Tanninsfromthelatterproduceamuchstrongerblackwaterthanleavesetcbutaclearerstainedwaterwithvirtuallynoparticulate.ItistheresultofaseepageofTanninsfromthehardwoodwhereastheotherismainlytheresultofthedecompositionofsofterorganicmatter. HereinthesouthwestcornerofAustraliaIuseagedMalleeRoot(leftoverfromagriculturallandclearing)andageddrybranchesfromEucalypttreessuchasRedGumandfromsomeAcaciatrees.Allmakebeautifulhardscapematerialbutproduceprodigiousamountsoftanninsatfirstandneedtoeitherbepre-soakedortreatedwithPurigenifputdirectlyinthetank. Ifindthatittakesahugeamountofleavestomaintainorrestorethedesireddarknesstothewaterbuthumicmatterfromleavesandothersoftorganicbitsismoreimmediatelybeneficialtotheoverallhealthofthetank. Toaddorincreaseblackwater,asmallpieceofdriedbranchorrootisaddedtothetankuntilthedesireddarknessisachievedorfloatedinacontainer,thenaddingthedarkenedwatertothetankwater.Inbothcasesaverydarkwatercanbequicklyachieved. MyorganicallygrownAvocadotreeprovidesbeautifulleavesthatbreakdownslowlytoaskeletalstage,thentobeneficialhumus. ManyspeciesofNewWorldCichlids,AustralianandNewGuineaspeciesandLoricaridsfrommanyplacesdonotseemtohavebeenbotheredbythehardwoodtanninandappeartohaveenjoyedandbenefitedfromthesofterhumicmatter. Reply Hello,whyfinegravelvssand? Regards tc Reply Sandisnotrecommendedforplantedaquariums.Thesandcanpackverytightlyanddoesallowformovementofwaterandnutrientsthroughthesubstrate.Afinegravelworksbestwhengrowingplants.SandisOKtouseifafish-onlyaquarium.Youdon’tneedathickbed,justaninchorso. Reply Hithere.Greatarticle!IaddeddriedCatappaleavesslowly(2x8″)tomy20glestablishedtank,waitedafewdays.Oncetheysankiaddedacouplemore.When theysankthetanninsleachedout&Iaddedafewmore.Itgotnice&amber&allfishwerehappy. WouldAfricandwarffrogsenjoyblackwater?Theyliveinaheavilyplanted10glwithcherryshrimp&Manzantowood.Itisfairlylowlight Reply HiDiane!Thesubstancesreleasedfromtheleavesarebeneficialtothetankandtoaquaticlife.Ithinkyourfrogswillbeperfectlyhappy! Reply HiIhavea450ltraquariumthatI’vesetupasblackwater.MyproblemisthatwhenIaddleavesandgetthedesiredtanofthewateritdoesn’ttakelongforthetanninstofadeandwaterstartstobecomeclear.Couldyoupleasegiveadviceonhowtopreventthis. Reply Tanninisageneraltermfororganiccompoundsthatarereleasedfromdecayingplantmaterials.Someofthetanninsaren’tverysolubleorbindwithothernaturallyoccurringsubstances,likeproteins.Tannincompoundsarereactive,andthecolorcanfade,dependingonyourtank’senvironment.Activatedcarbonfiltrationwillalsoremovethecolor.Experimentwithdifferentsourcesoftannintoseewhatismoststableinyourtank. 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