{"product_id":"black-widow-tetra-2-4cm","title":"Black Widow Tetra 2–4cm","description":"\u003cdiv class=\"nta-product\"\u003e\n\u003ch2 class=\"nta-title\"\u003eBlack Widow Tetra (\u003cem\u003eGymnocorymbus ternetzi\u003c\/em\u003e)\u003c\/h2\u003e\n\u003cp class=\"nta-tagline\"\u003eHardy, active and instantly recognisable, the Black Widow Tetra is a classic South American schooling fish with a deep-bodied profile, dark vertical bands and contrasting black fins. Kept in a proper group, \u003cem\u003eGymnocorymbus ternetzi\u003c\/em\u003e is an energetic and dependable community fish that suits a wide range of established freshwater aquariums.\u003c\/p\u003e\n\u003cdiv class=\"nta-box\"\u003e\n\u003ch3\u003eQuick Facts\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eScientific name: \u003cem\u003eGymnocorymbus ternetzi\u003c\/em\u003e\n\u003c\/li\u003e\n\u003cli\u003eCommon names: Black Widow Tetra, Black Skirt Tetra\u003c\/li\u003e\n\u003cli\u003eOrigin: South America\u003c\/li\u003e\n\u003cli\u003eAdult size: Approximately 5–6 cm\u003c\/li\u003e\n\u003cli\u003eTank size: 60L+ recommended\u003c\/li\u003e\n\u003cli\u003eDifficulty: 🟢 Easy\u003c\/li\u003e\n\u003cli\u003eTemperament: Generally peaceful and active\u003c\/li\u003e\n\u003cli\u003eSwimming level: Midwater\u003c\/li\u003e\n\u003cli\u003eBest kept: Groups of at least 6, with 8+ preferred where space allows\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"nta-box\"\u003e\n\u003ch3\u003eIs this for you?\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003e✔️ Perfect if:\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eYou want a hardy schooling tetra.\u003c\/li\u003e\n\u003cli\u003eYou enjoy active community aquariums.\u003c\/li\u003e\n\u003cli\u003eYou prefer bold black and silver contrast.\u003c\/li\u003e\n\u003cli\u003eYou want a straightforward species for a newer aquarist.\u003c\/li\u003e\n\u003cli\u003eYou have enough room for a proper group.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003e❌ Avoid if:\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eYou intend to keep only one or two individuals.\u003c\/li\u003e\n\u003cli\u003eYour aquarium is too small for an active school.\u003c\/li\u003e\n\u003cli\u003eYou keep very slow-moving or delicate long-finned fish.\u003c\/li\u003e\n\u003cli\u003eYou want a solitary centrepiece species.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"nta-box\"\u003e\n\u003ch3\u003eWhy choose Black Widow Tetras?\u003c\/h3\u003e\n\u003cp\u003eBlack Widow Tetras are long-established favourites because they combine strong visual contrast with hardy, adaptable behaviour.\u003c\/p\u003e\n\u003cp\u003eTheir deep silver-grey body is marked by distinctive dark vertical bands, while the dorsal and anal fins can develop rich black colouration that looks especially striking in a planted aquarium.\u003c\/p\u003e\n\u003cp\u003eThey are active schooling fish and become much more confident when kept in a proper group.\u003c\/p\u003e\n\u003cp\u003eThe species is also forgiving of a reasonably broad range of water conditions once established, making it a reliable choice for community aquariums.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"nta-box\"\u003e\n\u003ch3\u003eBenefits\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eHardy and beginner friendly\u003c\/li\u003e\n\u003cli\u003eDistinctive black and silver colouration\u003c\/li\u003e\n\u003cli\u003eActive schooling behaviour\u003c\/li\u003e\n\u003cli\u003eGenerally peaceful temperament\u003c\/li\u003e\n\u003cli\u003eEasy to feed\u003c\/li\u003e\n\u003cli\u003eAdaptable once established\u003c\/li\u003e\n\u003cli\u003eExcellent for planted community aquariums\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"nta-box nta-warning\"\u003e\n\u003ch3\u003eCare made simple\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eTemperature: Approximately 20–26°C\u003c\/li\u003e\n\u003cli\u003epH: Approximately 6.0–7.5\u003c\/li\u003e\n\u003cli\u003eWater: Clean, stable and well oxygenated\u003c\/li\u003e\n\u003cli\u003eDiet: Omnivorous\u003c\/li\u003e\n\u003cli\u003eStaple foods: Quality flakes and appropriately sized pellets\u003c\/li\u003e\n\u003cli\u003eSupplement with: Brine shrimp, daphnia and bloodworms\u003c\/li\u003e\n\u003cli\u003eFlow: Gentle to moderate\u003c\/li\u003e\n\u003cli\u003eSetup: Plants around the sides and rear with open swimming space\u003c\/li\u003e\n\u003cli\u003eRegular water changes help maintain strong colour and condition.\u003c\/li\u003e\n\u003cli\u003eKeep in a proper social group.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"nta-box\"\u003e\n\u003ch3\u003ePairs perfectly with\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eOther peaceful tetras\u003c\/li\u003e\n\u003cli\u003eRasboras\u003c\/li\u003e\n\u003cli\u003eCorydoras\u003c\/li\u003e\n\u003cli\u003eSmall peaceful loaches\u003c\/li\u003e\n\u003cli\u003eGouramis\u003c\/li\u003e\n\u003cli\u003eOther peaceful community fish of a similar size\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"nta-highlight\"\u003e\n\u003cstrong\u003eNTA Insight:\u003c\/strong\u003e\u003cbr\u003e\nBlack Widow Tetras are much better fish in a group than they are as single specimens. Six should be treated as a practical minimum, while a larger group gives you more natural schooling, better confidence and less chance of one fish repeatedly bothering the same tank mate.\n\u003c\/div\u003e\n\u003cdiv class=\"nta-box\"\u003e\n\u003ch3\u003eFAQ\u003c\/h3\u003e\n\u003cdetails\u003e\u003csummary\u003eWhat is the scientific name of the Black Widow Tetra?\u003c\/summary\u003e\u003cp\u003eThe accepted scientific name is \u003cem\u003eGymnocorymbus ternetzi\u003c\/em\u003e.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eIs the Black Widow Tetra the same as the Black Skirt Tetra?\u003c\/summary\u003e\u003cp\u003eYes. Black Widow Tetra and Black Skirt Tetra are common names used for \u003cem\u003eGymnocorymbus ternetzi\u003c\/em\u003e.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eHow large do Black Widow Tetras grow?\u003c\/summary\u003e\u003cp\u003eAdults generally reach approximately 5–6 cm.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eHow many should I keep?\u003c\/summary\u003e\u003cp\u003eKeep at least six, with larger groups preferred where aquarium size allows.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eAre Black Widow Tetras peaceful?\u003c\/summary\u003e\u003cp\u003eThey are generally peaceful community fish when kept in a proper group, although normal chasing and social sparring can occur.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eDo Black Widow Tetras nip fins?\u003c\/summary\u003e\u003cp\u003eThey can occasionally nip slow-moving or long-finned tank mates, particularly when kept in groups that are too small. A proper school helps direct their social behaviour toward one another.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eWhat should I feed them?\u003c\/summary\u003e\u003cp\u003eOffer quality flakes or small pellets as a staple and supplement with live or frozen foods such as brine shrimp, daphnia and bloodworms.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eCan Black Widow Tetras live with shrimp?\u003c\/summary\u003e\u003cp\u003eAdult shrimp may coexist with them in a well-planted aquarium, but small shrimp and shrimplets should be considered potential food.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eDo Black Widow Tetras need a heater?\u003c\/summary\u003e\u003cp\u003eA heater is usually recommended where room temperature is not consistently within their preferred range.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eCan Black Widow Tetras breed in aquariums?\u003c\/summary\u003e\u003cp\u003eYes. They are egg-scattering fish and provide no parental care, so adults may eat eggs and fry unless a dedicated breeding setup is used.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eAre Black Widow Tetras suitable for beginners?\u003c\/summary\u003e\u003cp\u003eYes. Their hardiness, straightforward feeding requirements and adaptable nature make them a good beginner community fish once the aquarium is properly cycled.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eHow long do Black Widow Tetras live?\u003c\/summary\u003e\u003cp\u003eWith clean water, good nutrition and appropriate social conditions, they commonly live for around 3–5 years and sometimes longer.\u003c\/p\u003e\u003c\/details\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e","brand":"Pisces Aquatics","offers":[{"title":"Default","offer_id":43244085477585,"sku":"22005","price":7.95,"currency_code":"AUD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0608\/5771\/2849\/files\/black-widow-tetra-2-4cm-nta_9b13e79d-091d-40df-a6dd-e7f61e759efe.jpg?v=1786655098","url":"https:\/\/nanotanksaustralia.com.au\/products\/black-widow-tetra-2-4cm","provider":"Nano Tanks Australia","version":"1.0","type":"link"}