{"product_id":"blueline-angelfish","title":"Blueline Angelfish","description":"\u003cp\u003eThe Blueline Angelfish (\u003cem\u003eChaetodontoplus septentrionalis\u003c\/em\u003e) is a marine angelfish recognized by a golden-brown adult body crossed by fine wavy blue lines and finished with a yellow tail. Its laterally compressed body allows it to move through reef structure while its patterned fins and deliberate movements create a distinctive display. Natural variation in age, origin, lighting, and individual pattern can affect appearance. Adult care requirements apply regardless of the size at purchase.\u003c\/p\u003e\n\u003cp\u003eNative to Northwestern Pacific, from the Malay Peninsula to southern Japan, this fish is associated with reef habitat offering shelter, feeding surfaces, and protected routes between rock formations. Its daily activity includes inspecting crevices and picking small food items from established reef surfaces. Blueline juveniles have a dark body with yellow markings rather than adult blue scribbling; allow shaded retreats and confirm food intake.\u003c\/p\u003e\n\u003cp\u003eA healthy adult may reach approximately \u003cstrong\u003e8.7 inches (22 cm)\u003c\/strong\u003e, so plan a mature aquarium of at least \u003cstrong\u003e180 gallons\u003c\/strong\u003e. With suitable space, steady feeding, and appropriate companions, it can become an engaging long-term aquarium resident. Aquarium volume, layout, feeding access, and adult compatibility should be considered together before introducing the fish.\u003c\/p\u003e\u003ch2\u003eQuick Care Guide\u003c\/h2\u003e\u003cp\u003e\u003cstrong\u003eCare Level:\u003c\/strong\u003e Moderate\u003cbr\u003e\u003cstrong\u003eMinimum Tank Size:\u003c\/strong\u003e 180 Gallons\u003cbr\u003e\u003cstrong\u003eAdult Size:\u003c\/strong\u003e Up to 8.7 inches (22 cm)\u003cbr\u003e\u003cstrong\u003eTemperament:\u003c\/strong\u003e Semi-Aggressive\u003cbr\u003e\u003cstrong\u003eDiet:\u003c\/strong\u003e Omnivore\u003cbr\u003e\u003cstrong\u003eReef Safe:\u003c\/strong\u003e No\u003cbr\u003e\u003cstrong\u003eRegion:\u003c\/strong\u003e Northwestern Pacific, from the Malay Peninsula to southern Japan\u003cbr\u003e\u003cstrong\u003eScientific Name:\u003c\/strong\u003e \u003cem\u003eChaetodontoplus septentrionalis\u003c\/em\u003e\u003c\/p\u003e\u003ch2\u003eTank Requirements\u003c\/h2\u003e\u003cp\u003eProvide a fully cycled, well-established marine aquarium with a minimum volume of 180 gallons for adult housing. Its deep adult body needs substantial turning room as well as a clear route along the length of the display. A taller, narrow aquarium should not be treated as equivalent to a broad display simply because the volumes match.\u003c\/p\u003e\n\u003cp\u003eArrange stable rock formations into caves, overhangs, and connected passages while retaining open water at the front and above the structure. Retreats should comfortably accommodate the adult without forcing it to scrape its sides or fins. Multiple entrances help prevent a dominant tankmate from trapping the fish inside a single cave.\u003c\/p\u003e\n\u003cp\u003eMature rockwork provides security and places for natural browsing between prepared meals. An aquarium covered in clean, newly installed rock does not supply the same feeding opportunities as an established reef surface. Blueline juveniles have a dark body with yellow markings rather than adult blue scribbling; allow shaded retreats and confirm food intake.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eSecure the aquascape before adding livestock.\u003c\/strong\u003e Rest heavy structures on a stable base and leave space for cleaning around them. Although this angelfish does not require a particular substrate, a clean sand bed or a well-maintained bare bottom should allow waste to be removed without repeatedly disturbing its shelters.\u003c\/p\u003e\n\u003cp\u003eProvide efficient biological filtration, regular mechanical waste removal, and an appropriately sized protein skimmer. Frequent feeding increases the nutrient load, and a system that holds acceptable readings while lightly stocked may need additional capacity before a substantial angelfish is added.\u003c\/p\u003e\n\u003cp\u003eMaintain moderate, varied water movement with calmer areas behind the rockwork. Good surface agitation and dependable oxygenation are important, especially overnight. Avoid directing a powerful unbroken jet into the fish's preferred shelter.\u003c\/p\u003e\n\u003cp\u003eUse a secure cover and protect overflow openings. During introduction, reduce disturbance and let the fish choose a retreat. Keep the daily lighting schedule predictable so feeding and resting behavior can settle into a routine.\u003c\/p\u003e\n\u003cp\u003eThe stated volume is a starting point for one adult, not an allowance for several competing angelfish. Additional large or territorial residents require more space, more visual barriers, and a practical plan to separate fish if compatibility changes.\u003c\/p\u003e\u003ch2\u003eDiet and Feeding\u003c\/h2\u003e\u003cp\u003eThe Blueline Angelfish is an omnivorous angelfish with an important benthic feeding component. Sponge-containing angelfish preparations, marine algae, and varied marine proteins should form a regular feeding rotation.\u003c\/p\u003e\n\u003cp\u003eNatural browsing is useful enrichment, but it is not a substitute for a complete prepared-food routine. Rockwork may look mature while supplying too little nutrition to maintain a newly introduced angelfish.\u003c\/p\u003e\n\u003cp\u003eOffer a balanced selection that includes:\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003e\u003cp\u003eSponge-containing marine angelfish preparations\u003c\/p\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cp\u003eSpirulina-based marine pellets or flakes\u003c\/p\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cp\u003eMarine algae and nori\u003c\/p\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cp\u003eFrozen mysis shrimp\u003c\/p\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cp\u003eEnriched brine shrimp\u003c\/p\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cp\u003eFinely chopped clam or other marine seafood\u003c\/p\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cp\u003eBalanced frozen marine omnivore blends\u003c\/p\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003eOffer two to three small meals daily, adjusting portions to age, body condition, and the amount of food actually consumed. Growing juveniles and thin new arrivals often need additional small opportunities rather than one oversized feeding. Remove uneaten portions before they collect in caves or around filtration intakes.\u003c\/p\u003e\n\u003cp\u003eOffer algae on a secure clip and place small prepared portions where the fish can approach without being chased. More than one feeding location can reduce competition.\u003c\/p\u003e\n\u003cp\u003eWatch for actual swallowing, not simply interest in food. A fish that repeatedly mouths and rejects every item may still be losing condition. A pinched abdomen, persistent hiding, or an established tankmate intercepting every meal calls for a change in the feeding arrangement.\u003c\/p\u003e\n\u003cp\u003eOnce established, many individuals accept a mixture of frozen and prepared foods. Introduce new textures gradually while continuing dependable foods so dietary variety does not come at the expense of consistent intake.\u003c\/p\u003e\n\u003cp\u003eSponge-containing food should remain a recurring part of the menu, not a one-time acclimation aid. Algae and seafood broaden the diet but do not justify reducing it to a single ingredient.\u003c\/p\u003e\n\u003cp\u003eAvoid using unenriched brine shrimp as the sole long-term ration. Freshwater feeder fish and terrestrial meat are unnecessary and poorly matched to this animal's feeding ecology. A varied marine-based menu, suitable portion sizes, and routine observation support long-term body condition.\u003c\/p\u003e\n\u003cp\u003eDo not assume that a fish refusing food will recover simply by being left in a busy display. Reduce competition, check water quality, and provide a calm feeding area when needed. Persistent refusal to eat should be addressed before substantial weight loss develops.\u003c\/p\u003e\u003ch2\u003eTemperament and Tankmates\u003c\/h2\u003e\u003cp\u003eThe Blueline Angelfish is best described as \u003cstrong\u003esemi-aggressive\u003c\/strong\u003e. Territorial behavior is most likely around established rockwork and toward other angelfish with similar shapes, patterns, or feeding habits.\u003c\/p\u003e\n\u003cp\u003eA single specimen is the most predictable arrangement. Multiple large angelfish should be considered only in much larger, carefully planned displays with adequate shelter and separate feeding opportunities.\u003c\/p\u003e\n\u003cp\u003ePotential companions include appropriately sized wrasses, tangs, rabbitfish, and robust community fish, selected for the aquarium's actual space and the individual fish's temperament.\u003c\/p\u003e\n\u003cp\u003eAvoid crowding the aquarium with visually similar competitors. Even otherwise compatible species can become difficult neighbors when they compete for the same cave or feeding position.\u003c\/p\u003e\n\u003cp\u003eIntroduce new residents thoughtfully. An acclimation box can help evaluate reactions, but behavior during a short introduction does not guarantee permanent compatibility. Ensure the box provides appropriate water movement and does not force the fish into continuous bright light or contact with aggressive tankmates.\u003c\/p\u003e\n\u003cp\u003eObserve interactions at feeding time and near preferred resting sites. Repeated pursuit, torn fins, a fish pressed into one corner, or persistent refusal to leave a cave are signs that the arrangement needs attention. Occasional displays should not be confused with ongoing harassment that prevents normal activity.\u003c\/p\u003e\n\u003cp\u003eProvide visual breaks between territories and keep a separation option available. Aquascaping can reduce encounters, but it cannot make fundamentally incompatible fish safe companions. Adult behavior may become more assertive as a juvenile matures or as a new fish changes the social order.\u003c\/p\u003e\n\u003cp\u003eDo not use a small juvenile's initially tolerant behavior to predict the temperament of the full-grown adult. Plan compatibility around the mature fish and reassess after growth, spawning behavior, or major changes to the display.\u003c\/p\u003e\u003ch2\u003eReef Compatibility\u003c\/h2\u003e\u003cp\u003eThe Blueline Angelfish is \u003cstrong\u003enot considered reef safe\u003c\/strong\u003e. A fish-only display with mature rock provides the most predictable environment.\u003c\/p\u003e\n\u003cp\u003ePotential targets include fleshy stony-coral tissue, soft-coral polyps, zoanthids, clam mantles, and attached reef invertebrates. Sponges and tunicates are especially relevant because they are part of the feeding ecology of many large angelfishes.\u003c\/p\u003e\n\u003cp\u003eA fish that leaves corals alone immediately after introduction may change its behavior later. Growth, changing food availability, and individual preferences can alter compatibility even in a previously settled aquarium.\u003c\/p\u003e\n\u003cp\u003eFrequent varied feeding and substantial mature rockwork may provide alternative browsing opportunities, but they cannot guarantee coral safety. Do not purchase a specimen on the assumption that a full stomach will reliably prevent nipping.\u003c\/p\u003e\n\u003cp\u003eMobile cleanup-crew animals are generally less relevant to its diet than attached reef organisms, but this should not be interpreted as a guarantee for every small or newly molted invertebrate. Observe the actual individual and protect valuable livestock.\u003c\/p\u003e\n\u003cp\u003eIf attempting a reef placement, have a practical removal plan before introduction. Moving a fish from elaborate coral rockwork can be difficult, and repeated nipping may prevent a coral from expanding well before obvious tissue loss occurs.\u003c\/p\u003e\n\u003cp\u003eA selected collection of hardy corals does not establish universal reef compatibility. Avoid describing this angelfish as harmless to all SPS, LPS, soft corals, or clams; individual behavior and the animals present determine the result.\u003c\/p\u003e\u003ch2\u003eWater Parameters\u003c\/h2\u003e\u003cp\u003e\u003cstrong\u003eTemperature:\u003c\/strong\u003e 75–80°F\u003cbr\u003e\u003cstrong\u003eSpecific Gravity:\u003c\/strong\u003e 1.024–1.026\u003cbr\u003e\u003cstrong\u003epH:\u003c\/strong\u003e 8.1–8.4\u003cbr\u003e\u003cstrong\u003eAlkalinity:\u003c\/strong\u003e 8–12 dKH\u003c\/p\u003e\u003cp\u003eMaintain stable marine conditions with undetectable ammonia and nitrite, reliable oxygenation, and controlled nutrient accumulation. Consistent maintenance is especially important in a system receiving the frequent small feedings that angelfish benefit from.\u003c\/p\u003e\n\u003cp\u003eAvoid rapid changes in temperature, salinity, or pH. Steady conditions within an appropriate range are preferable to frequent corrective additions made solely to chase an exact number.\u003c\/p\u003e\n\u003cp\u003eCheck salinity with a calibrated instrument and keep top-off consistent. Clean mechanical filtration, remove trapped food, and perform water changes appropriate to the actual nutrient load. Quarantine new fish in a stable, fully supported system, and do not allow a bare treatment aquarium to become a source of ammonia stress.\u003c\/p\u003e\n\u003cp\u003eAcclimate according to the water conditions of the source and receiving system, keeping handling calm and deliberate. Angelfish have cheek spines that can catch in mesh; use suitable containers and careful transfer methods to reduce injury.\u003c\/p\u003e\u003ch2\u003eCommon Considerations\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003e\u003cp\u003e\u003cstrong\u003eAdult Housing:\u003c\/strong\u003e Plan for approximately 8.7 inches (22 cm) and at least 180 gallons, with a suitable footprint and additional space when keeping other territorial or active fish.\u003c\/p\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cp\u003e\u003cstrong\u003eSpecies-Specific Needs:\u003c\/strong\u003e Blueline juveniles have a dark body with yellow markings rather than adult blue scribbling; allow shaded retreats and confirm food intake.\u003c\/p\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cp\u003e\u003cstrong\u003eReliable Feeding:\u003c\/strong\u003e Provide a varied omnivorous menu and observe actual food intake; mature rockwork supports browsing but cannot replace a complete feeding routine.\u003c\/p\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cp\u003e\u003cstrong\u003eCompatibility:\u003c\/strong\u003e Semi-Aggressive behavior requires suitable companions and monitoring. Corals and attached reef invertebrates may be damaged; fish-only housing is preferred.\u003c\/p\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cp\u003e\u003cstrong\u003eLong-Term Observation:\u003c\/strong\u003e Monitor body condition, breathing, feeding response, and social interactions as the fish grows. A quiet introduction and regular observation help identify problems before they become persistent.\u003c\/p\u003e\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"TSA Fish","offers":[{"title":"Tiny (\u003c2\")","offer_id":52273913921834,"sku":"ANGELxBlueLineT","price":399.99,"currency_code":"USD","in_stock":false},{"title":"Small (2.1-2.5\")","offer_id":52074437640490,"sku":"ANGELxBlueLineS","price":389.99,"currency_code":"USD","in_stock":false},{"title":"SM (2.6-3.5\")","offer_id":51137518403882,"sku":"ANGELxBlueLineSM","price":779.99,"currency_code":"USD","in_stock":false},{"title":"Medium (3.6-4.5\")","offer_id":51289175195946,"sku":"ANGELxBlueLineM","price":824.99,"currency_code":"USD","in_stock":false},{"title":"ML (4.6-5.5\")","offer_id":52074437673258,"sku":"ANGELxBlueLineML","price":899.99,"currency_code":"USD","in_stock":false},{"title":"Large (5.6-6.5\")","offer_id":52074437706026,"sku":"ANGELxBlueLineL","price":974.99,"currency_code":"USD","in_stock":false},{"title":"XL (6.6-7.5\")","offer_id":52074437738794,"sku":"ANGELxBlueLineXL","price":1079.99,"currency_code":"USD","in_stock":false},{"title":"XX (7.6-8.5\")","offer_id":52074437771562,"sku":"ANGELxBlueLineXX","price":1349.99,"currency_code":"USD","in_stock":false},{"title":"SHOW (8.6-10.5\")","offer_id":52074437804330,"sku":"ANGELxBlueLineSH","price":1549.99,"currency_code":"USD","in_stock":false},{"title":"JUMBO (10.6\"+)","offer_id":52074437837098,"sku":"ANGELxBlueLineJ","price":1579.99,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0783\/0873\/7322\/files\/tsa-fish-blueline-angelfish-1257021518.png?v=1790973618","url":"https:\/\/topshelfaquatics.com\/products\/blueline-angelfish","provider":"Top Shelf Aquatics","version":"1.0","type":"link"}