{"product_id":"threadfin-rainbowfish-iriatherina-werneri-freshwater","title":"Threadfin Rainbowfish (Iriatherina werneri)","description":"\u003cdiv style=\"font-family:Georgia,serif;color:#1a1a1a;max-width:860px;line-height:1.7;\"\u003e\n\u003cdiv style=\"background:#E3F2FD;border-left:4px solid #1E88E5;padding:10px 14px;margin:0 0 14px;font-size:0.95em;\"\u003e\n\u003cstrong\u003eIn-store pickup only.\u003c\/strong\u003e Your order is reserved, we hold off on bagging until you arrive so it stays healthy in its display tank.\n\u003c\/div\u003e\n\u003cp\u003eThe \u003cstrong\u003eThreadfin Rainbowfish\u003c\/strong\u003e (\u003cem\u003eIriatherina werneri\u003c\/em\u003e) is one of the most spectacular small fish in the freshwater hobby. Males carry absurdly long filamentous rays trailing from the second dorsal and anal fins, tipped in red and black, plus a lyre-shaped tail with red-edged lobes. When two males square off they flare everything at once and flick those threads at each other, and a group of them in a planted tank does this all day long. The body is barely an inch and a half, so all of that display is packed into a genuinely tiny fish. These are grown-out, medium-size fish, and all commercially available stock is captive bred. Browse the rest of our \u003ca href=\"https:\/\/squeakysaquatics.com\/collections\/fish\"\u003elive fish\u003c\/a\u003e and \u003ca href=\"https:\/\/squeakysaquatics.com\/collections\/fresh-water\"\u003efreshwater supplies\u003c\/a\u003e to build the right tank for them.\u003c\/p\u003e\n\u003cdiv style=\"background:#E3F2FD;border-left:4px solid #1E88E5;padding:10px 14px;margin:14px 0;font-size:0.95em;\"\u003e\n\u003cstrong\u003eThe difficulty here is not water, it is food.\u003c\/strong\u003e Threadfins tolerate a huge range of pH and hardness, so they are easy on that front. What kills them is a \u003cstrong\u003emouth too small for normal fish food\u003c\/strong\u003e combined with a slow, deliberate feeding style. Put them in a busy community tank and they quietly starve while everything else eats. Plan the tankmates and the food around that and they are straightforward.\n\u003c\/div\u003e\n\u003ch3 style=\"margin:14px 0 4px;font-size:1.05em;font-weight:600;line-height:1.25;border-left:4px solid #1E88E5;padding-left:8px;\"\u003eCare Guide\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eTank size:\u003c\/strong\u003e a 20 gallon or a 24 by 12 inch footprint is the sensible minimum. They are small but they are constantly moving, and males need room to spread out and display.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eGroup size:\u003c\/strong\u003e six is the floor, \u003cstrong\u003eten or more is where they come alive\u003c\/strong\u003e. Include several males. A group of males displaying to each other is the entire reason to keep this species, and a lone male never shows his best.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFood must be tiny:\u003c\/strong\u003e crushed flake, \u003ca href=\"https:\/\/squeakysaquatics.com\/products\/hikari-micro-pellets\"\u003emicro pellets\u003c\/a\u003e, \u003ca href=\"https:\/\/squeakysaquatics.com\/products\/xtreme-nano-slow-sinking-pellets-nano-fish-food\"\u003enano pellets\u003c\/a\u003e, \u003ca href=\"https:\/\/squeakysaquatics.com\/products\/sfbb-baby-brine-shrimp-cube-1-75oz\"\u003ebaby brine shrimp\u003c\/a\u003e, and \u003ca href=\"https:\/\/squeakysaquatics.com\/products\/hikari-bio-pure-freeze-dried-daphnia\"\u003edaphnia\u003c\/a\u003e. Live and frozen small foods bring out the best colour. Feed small amounts more often rather than one big feeding.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWater parameters:\u003c\/strong\u003e 72 to 86°F, pH 5.0 to 8.0, hardness anywhere from very soft to moderately hard. Genuinely adaptable, which is why they suit so many setups.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFlow:\u003c\/strong\u003e gentle. A \u003ca href=\"https:\/\/squeakysaquatics.com\/products\/hikari-bacto-surge-foam-filter-sponge-freshwater-saltwater\"\u003esponge filter\u003c\/a\u003e is ideal. Strong current pins those long fins flat and stops the display.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAquascape:\u003c\/strong\u003e dense planting around the edges with clear open water in the middle for displaying. \u003ca href=\"https:\/\/squeakysaquatics.com\/products\/java-moss-taxiphyllum-barbieri-freshwater-moss\"\u003eJava moss\u003c\/a\u003e and floating plants such as \u003ca href=\"https:\/\/squeakysaquatics.com\/products\/frogbit-portion-cup-limnobium-spongia\"\u003efrogbit\u003c\/a\u003e give them the dappled light they like.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLid:\u003c\/strong\u003e recommended. They are small surface-oriented fish and can jump when startled.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBreeding:\u003c\/strong\u003e females scatter a few eggs daily among fine-leaved plants or spawning mops over several days. Adults largely ignore the eggs, but the fry are very small and delicate and need powdered food or live infusoria plus frequent small water changes. Raising them is the hard part, not getting them to spawn.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3 style=\"margin:14px 0 4px;font-size:1.05em;font-weight:600;line-height:1.25;border-left:4px solid #1E88E5;padding-left:8px;\"\u003eSpecifications\u003c\/h3\u003e\n\u003ctable style=\"border-collapse:collapse;width:100%;max-width:640px;\"\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #BBDEFB;padding:6px 10px;\"\u003e\u003cstrong\u003eScientific name\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #BBDEFB;padding:6px 10px;\"\u003e\u003cem\u003eIriatherina werneri\u003c\/em\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #BBDEFB;padding:6px 10px;\"\u003e\u003cstrong\u003eCommon names\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #BBDEFB;padding:6px 10px;\"\u003eThreadfin Rainbowfish, Featherfin Rainbowfish\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #BBDEFB;padding:6px 10px;\"\u003e\u003cstrong\u003eOrigin\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #BBDEFB;padding:6px 10px;\"\u003eSouthern New Guinea and northern Australia. Captive bred.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #BBDEFB;padding:6px 10px;\"\u003e\u003cstrong\u003eMax size\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #BBDEFB;padding:6px 10px;\"\u003eBody around 1.5 inches (4 cm), males longer with fin extensions\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #BBDEFB;padding:6px 10px;\"\u003e\u003cstrong\u003eCare level\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #BBDEFB;padding:6px 10px;\"\u003eIntermediate, due to feeding\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #BBDEFB;padding:6px 10px;\"\u003e\u003cstrong\u003eTemperament\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #BBDEFB;padding:6px 10px;\"\u003eVery peaceful, timid\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #BBDEFB;padding:6px 10px;\"\u003e\u003cstrong\u003eMinimum group\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #BBDEFB;padding:6px 10px;\"\u003e6, ideally 10 or more\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #BBDEFB;padding:6px 10px;\"\u003e\u003cstrong\u003eMinimum tank\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #BBDEFB;padding:6px 10px;\"\u003e20 gallons\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #BBDEFB;padding:6px 10px;\"\u003e\u003cstrong\u003eTemperature\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #BBDEFB;padding:6px 10px;\"\u003e72 to 86°F\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #BBDEFB;padding:6px 10px;\"\u003e\u003cstrong\u003epH\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #BBDEFB;padding:6px 10px;\"\u003e5.0 to 8.0, very adaptable\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #BBDEFB;padding:6px 10px;\"\u003e\u003cstrong\u003eDiet\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #BBDEFB;padding:6px 10px;\"\u003eMicropredator, very small foods only\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #BBDEFB;padding:6px 10px;\"\u003e\u003cstrong\u003eBreeding\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #BBDEFB;padding:6px 10px;\"\u003eEgg scatterer among fine plants\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #BBDEFB;padding:6px 10px;\"\u003e\u003cstrong\u003ePickup\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #BBDEFB;padding:6px 10px;\"\u003eIn-store only\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\u003ch3 style=\"margin:14px 0 4px;font-size:1.05em;font-weight:600;line-height:1.25;border-left:4px solid #1E88E5;padding-left:8px;\"\u003eCompatibility\u003c\/h3\u003e\n\u003cp\u003ePeaceful with everything, but easily bullied off its food, so the tankmate list is shorter than you would expect for such a harmless fish. The best companions are other small, slow, gentle species: \u003ca href=\"https:\/\/squeakysaquatics.com\/products\/paskai-rainbowfish-pseudomugil-paskai-freshwater\"\u003ePaskai Rainbowfish\u003c\/a\u003e and other blue eyes are the classic pairing, along with \u003ca href=\"https:\/\/squeakysaquatics.com\/products\/pygmy-cory-corydoras-pygmaeus-freshwater\"\u003ePygmy Cories\u003c\/a\u003e, \u003ca href=\"https:\/\/squeakysaquatics.com\/products\/celestial-pearl-danio-danio-margaritatus-freshwater\"\u003eCelestial Pearl Danios\u003c\/a\u003e, \u003ca href=\"https:\/\/squeakysaquatics.com\/products\/ember-tetra-hyphessobrycon-amandae-freshwater\"\u003eEmber Tetras\u003c\/a\u003e, and \u003ca href=\"https:\/\/squeakysaquatics.com\/products\/assorted-dwarf-neocaridina-shrimp\"\u003edwarf shrimp\u003c\/a\u003e.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eTwo things to avoid.\u003c\/strong\u003e First, anything fast and greedy: barbs, most danios, and larger tetras will clear the food before a threadfin has decided to eat. Second, \u003cstrong\u003efin nippers\u003c\/strong\u003e. Those trailing filaments are irresistible to a nipper, and once they are bitten off the fish loses the feature you paid for. Larger rainbowfish such as \u003ca href=\"https:\/\/squeakysaquatics.com\/products\/boesemani-rainbowfish-melanotaenia-boesemani-freshwater\"\u003eBoesemani\u003c\/a\u003e are relatives but far too big and boisterous to share a tank with these.\u003c\/p\u003e\n\u003ch3 style=\"margin:14px 0 4px;font-size:1.05em;font-weight:600;line-height:1.25;border-left:4px solid #1E88E5;padding-left:8px;\"\u003eRecommended Foods \u0026amp; Supplies\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/squeakysaquatics.com\/products\/hikari-micro-pellets\"\u003eHikari Micro Pellets\u003c\/a\u003e, sized for a mouth this small\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/squeakysaquatics.com\/products\/xtreme-nano-slow-sinking-pellets-nano-fish-food\"\u003eXtreme Nano Slow-Sinking Pellets\u003c\/a\u003e for slow deliberate eaters\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/squeakysaquatics.com\/products\/sfbb-baby-brine-shrimp-cube-1-75oz\"\u003eSFBB Baby Brine Shrimp\u003c\/a\u003e and \u003ca href=\"https:\/\/squeakysaquatics.com\/products\/hikari-bio-pure-freeze-dried-daphnia\"\u003eFreeze-Dried Daphnia\u003c\/a\u003e for colour and conditioning\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/squeakysaquatics.com\/products\/hikari-bacto-surge-foam-filter-sponge-freshwater-saltwater\"\u003eHikari Bacto-Surge Sponge Filter\u003c\/a\u003e for gentle, low-flow filtration\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/squeakysaquatics.com\/products\/java-moss-taxiphyllum-barbieri-freshwater-moss\"\u003eJava Moss\u003c\/a\u003e and \u003ca href=\"https:\/\/squeakysaquatics.com\/products\/frogbit-portion-cup-limnobium-spongia\"\u003eFrogbit\u003c\/a\u003e for cover, spawning sites, and softened light\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3 style=\"margin:14px 0 4px;font-size:1.05em;font-weight:600;line-height:1.25;border-left:4px solid #1E88E5;padding-left:8px;\"\u003eFAQ\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eHow do I tell males from females?\u003c\/strong\u003e\u003cbr\u003eIt is obvious once they mature. Males have the long trailing filaments on the dorsal and anal fins, extended pelvic fins, more colour, and slightly larger size. Females are plainer silver with short, ordinary fins. The fish in the photo is a male.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eShould I buy mostly males then?\u003c\/strong\u003e\u003cbr\u003eGet a mix, but make sure there are several males. Males display hardest when they are competing with each other and courting females, so a group with both sexes gives you far more action than males alone.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eAre they hard to keep?\u003c\/strong\u003e\u003cbr\u003eNot once you understand the one issue. Their water requirements are wide and forgiving. The problem is purely that they have tiny mouths and feed slowly, so they need small food and calm tankmates. Solve that and they are undemanding.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhy do the long fins look short on the fish in the store tank?\u003c\/strong\u003e\u003cbr\u003eYoung males have not grown them out yet, and filaments can also be worn down in a crowded holding tank. They regrow in good conditions with proper feeding, so a male with short threads today will usually develop them fully in your tank.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"Squeaky's Aquatics","offers":[{"title":"Default Title","offer_id":49027286368475,"sku":"SQ-RAINBOWTHREADF","price":12.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0767\/5209\/3403\/files\/Rainbow_Threadfin.jpg?v=1785070870","url":"https:\/\/squeakysaquatics.com\/products\/threadfin-rainbowfish-iriatherina-werneri-freshwater","provider":"Squeaky's Aquatics","version":"1.0","type":"link"}