That Fish Blog – Aquarium Advice and Information

Eileen here. Below is a glossary of some general aquarium hobby terms. Once complete, we’ll try and publish the Aquarist’s Glossary of Term’s somewhere online, but in the meantime, hopefully it helps in pieces. Check out part 1 and part 2 here.

General Aquarium Hobby Terms:

• Compatibility: This refers to how well tankmates are likely to get along. For example, Neon Tetras are compatible with Zebra Danios – they would be fine together in a tank. A ten inch Peacock Grouper however, would NOT be compatible with a one inch Skunk Cleaner Shrimp – the shrimp would likely end up a meal pretty fast.
• Coral “Frag”: A “frag” is a small piece or colony of coral, often mounted on a small artificial plug. Frags have become very popular in recent years as an inexpensive and environmental way of trading and acquiring smaller pieces of the large and sometimes rare or expensive coral colonies available in the hobby.
• Filtration: There are three main types of filtration used in the aquarium trade – chemical, mechanical and biological. Chemical filtration uses materials like carbon or resins to remove or neutralize chemical compounds on the water. Mechanical filtration physically removes debris and waste using mesh, sponges or other materials. Biological filtration uses bacteria, plants or other living materials to remove waste from the water. A complete filtration system will use all three of these methods in a system. Different types of filters that use some or all three of these methods include power/hang-on filters, wet/dry filters, undergravel filters, canister filters, fluidized beds and others.
• Hardiness/ Difficulty: Both of these terms are used to describe how easy something is to care for. Their meanings tend to be relative opposites of each other and most places only use one, but they are in fact seperate terms. An item that is “hardy” is generally easy to care for (or hard to kill, dependong on how you look at it). A “difficult” item often has specific needs, a tricky diet or is very delicate. Beginning aquarists should look for a hardy fish with low difficulty. Keep in mind however that hardiness does not always equal easy; research your choices carefully!
• Kelvin Rating: The “degrees Kelvin” are a way of measuring the temperature of the light, not to be confused with normal temperature of heat as measures in Celcius and Fahrenheit. While the technical terms and measurements of the Kelvin scale can be found in detail marine aquarium publications and on the Internet, the important thing for the average aquarist to know is the higher the number, the more blue the light. (On the good old “ROY G. BIV” rainbow scale, low Kelvin temperatures are on the R side while high temperatures are at the V). Most saltwater and reef aquariums use higher Kelvin lighting than freshwater aquariums.
• Lighting: The most common types of lighting for aquariums, in order of intensity, are fluorescent, compact fluorescent (also known as power compact), and metal halides with different classifications within each of those types. Actinic is also a type of bulb used and refers to blue lighting with a wavelength of around 420-460nm and is used in saltwater and reef tanks. Always research what lighting would be appropriate for your tank as well as what livestock is appropriate for use with your lighting.
• Live Rock: Live rock is used in saltwater aquariums as a natural decoration and foundation as well as for the benefits of the organisms growing in an on the rock. It is essentially rock that has been in the oceans for months or even years so that bacteria, algaes, plants, crustaceans, corals and other organisms populate and live on the rock. “Cultured live rock” refers to rock that is either manmade from concrete-like mixtures or is terrestrial rock and is placed in the ocean for a period of time to turn “live”. Live rock is also refered to as “cured” or “uncured”. “Uncured” rock is newly harvested rock that may not be fully cleaned of organisms that do not survive harvesting. “Cured” rock is usually much cleaner and stable and is safer for more established aquariums. Different types of rock are available from different regions, but the main difference between these varieties is simply the region it is harvested from and the shape or density of the rock. Tonga, Fiji, the Solomon Islands and the Caribbean are popular origin regions for live rock.
• “Reef Safe”/ “Invert Safe”: These two terms can refer to plants and animals or to products like medications. “Reef Safe” items are safe for tanks with polyps and corals while “Invert Safe” is a broader term that includes other animals like crabs, shrimp, anemones, snails and others. While some references use these terms interchangeably, they do not always mean the same thing. For example, hawkfish are generally considered “reef safe” in that they don’t actively eat or damage corals, but they are not “invert safe” since they prey on crustaceans.
• Starter fish: While these fish are usually very good for beginner aquariusts, the term “starter fish” usually refers to those fish which are considered hardy enough to use to start and cycle an aquarium. The spikes in ammonia, nitrite and nitrate during this cycling process can be dangerous to any livestock, but those typically used as starter fish are more likely to survive this process than others.
• Tank-raised/ Captive-bred/ Aquacultured: These three terms generally mean the same thing, although “aquacultured” is used more for corals, plants and invertebrates and “tank-raised” and “captive-bred” usually refer more to fish. “Aquaculture” by definition is the growing of freshwater and saltwater organisms under controlled conditions, much like agriculture is the growing of crops on the land. This can range from farms used to grow fish like catfish and tilapia for food production to breeding ornamental fish for the aquarium industry. Tank-raised and captive-bred fish are typically bred on a smaller scale than farms created for the food industry. Some tank-raised fish that are commonly available are fish like clownfish, dottybacks, gobies and some cardinalfish as well as a few freshwater fish like angelfish and discus. Tank-raised fish are often more resistant to aquarium-related diseases than wild-caught fish but can be vulnerable to diseases introduced by their wild-caught counterparts. Strict regulations and pressure on wild fish populations are making captive breeding of fish more common and tank-raised fish more sought-after in the aquarium trade.
• Territorial/ Aggressive: Some aquarists use these terms interchangeably but they have quite different meanings. “Territorial” fish or invertebrates establish and often actively (and potentially aggressively) defend a particular territory but do not necessarily harm other organisms that do not invade this territory. “Aggressive” fish may show some of the same behavior but do not do so to defend a certain area, but will instead attack and potentially harm any other organisms they may find threatening in a tank. A territorial fish (damsels, cichlids, dottybacks, etc.) can often be safely kept with other tankmates as long as they have enough territory to defend and other fish do not share this area, while tankmates for an aggressive animal (triggers, some cichlids, predators, mantis shrimp) must be chosen very carefully, if kept with any other tankmates at all.
• Tropical: Almost all plants and animals kept in the aquarium trade are tropical, both freshwater and saltwater. This term refers to their temperature, not their water conditions or where they come from. The tropics are geographically the are between the Tropic of Cancer (23.4º N latitude) and the Tropic of Capricorn (23.4º S latitude). In terms of climate, this usually refers to water temperatures of around 74-82º F, depending on the region. Some notable exceptions are goldfish, koi and a few saltwater fish from temperate regions (the area between the Tropics of Cancer and Capricorn and the Arctic and Antarctic Circles, including the moderate subtropic region). The aquarium fish from these regions have average water temperatures of around 65-72ºF.
• Water change: A water change as refered to within in the aquarium hobby is when an aquarist removes a portion of their tank water (usually 10-20%, once or twice a month) and replaces it with fresh, clean water. This is done to remove fish waste and to keep water levels appropriate, especially levels like nitrate and phosphate or even to promote breeding in some fish. A water change is not when an aquarist merely tops off a tank to replace water lost through evaporation – only pure water evaporates and salts, waste and other compounds are not removed when the water they are dissolved in evaporates.

Check out the 1st part of Eileen’s Aquarist’s Glossary of Terms here.

Water chemistry terms:

•  Alkalinity: Alkalinity is often confused with pH or water hardness. In technical terms, the alkalinity is the ability of a solution to neutralize acid. In an aquarium, this can be seen in changes in pH. The higher the alkalinity, the more difficult it is for the pH to change. pH levels above neutral (7.0 on a scale of 0-14) are also said to be “alkaline” or “basic” as opposed to levels below neutral are considered acidic.
• Brackish: Brackish environments are those found in between freshwater and saltwater environments and have a specific gravity of about 1.005 to 1.015 or a salinity of 0.5-30 ppt (parts per thousand). Common brackish water environments related to the aquarium trade are mangrove swamps, estuaries and bays.
• Carbon Dioxide: Carbon dioxide (CO₂) is a compound used by plants to produce oxygen in photosynthesis and a byproduct of respiration in which oxygen is used. CO₂ levels are important to monitor in heavily planted freshwater aquariums but are not as important in unplanted freshwater aquariums or in saltwater systems.
• Freshwater: Freshwater is water that does not have a significant salt level and is typically of most river or lake environments. Common freshwater environments that many aquarium-trade fish can be found in are the the Amazon River, African Rift Lakes, Australian rivers and South and Central American rivers. These are also referred to as aquatic environments.
• Nitrogen Cycle: The Nitrogen Cycle is used to descripe the process of converting ammonia (NH₄⁺) to nitrite(NO₂^–) to nitrate (NO₃^–). This process happens in any environment with organisms that produce ammonia and is conducted by nitrifying bacteria (nitrosomonas and nitrobacter). The levels of these three compounds are some of the most universal and important levels to monitor in home aquariums as they can be toxic to aquarium animals. Ammonia and nitrite can be especially toxic as they affect the ability of an animal’s gills to function correctly and the ability of an animial to absorb oxygen into its bloodstream. This is also known as the “Cycling Process” of an aquarium and can take 4-6 weeks in new aquariums or aquariums in which the biological filtration has been destroyed by water changes, medications or another cause.
• Ozone: Ozone (O₃) is a molecule made up of three oxygen atoms instead of the more stable 2-atom molecule (O₂). In aquariums and ponds, ozone is used to help control bacteria, disease and algae growth, to help remove very tiny debris particles from the water and for several other purposes. An “ozonizer” is used to pump a controlled amount of ozne into the aquarium. This is safe for most aquarium species (some animals like sharks can be very sensitive to ozone) but can quickly dry out and crack some rubber materials like tubing. Silicone tubing should be used with ozone and ozonizers.
• pH: The pH level is, technically speaking, the amount of free hydrogen ions in a substance. The pH level is calculated using mathematical logarithms and does not have a unit of measurement. This scale is measured from 0 to 14 (or -1 to 14 in some scientific circles) with 7.0 being considered “neutral”. Levels above 7.0 are considered “Basic” or “alkaline” while levels under 7.0 are considered “acidic”. Some common pH ranges in the aquarium trade are 8.0-8.4 for marine systems, 6.8-7.4 for most tropical freshwater fish like those from the Amazon River, and 7.8-8.4 for African Cichlids from Lake Malawi and Lake Victoria.
• Phosphate: Phosphate (PO₄) has many uses, from glass production and fertilizers to matches and fireworks. An excess of this nutrient in freshwater or saltwater systems can cause algae blooms, usually characterized by green water or greenish or blackish films on surfaces. It can be removed by special filters or filter media and usually enters an aquarium through overfeeding with phosphate-rich foods or though source water with high phosphate levels like well water or in heavily agricultural areas.
• Salinity/ Specific Gravity: Both of these terms are used to describe and measure the amount of salt in water. “Salinity” is mainly used in more scientific measurements and measures the amount of salt in parts per thousand (ppt or ⁰/₀₀). “Specific gravity” is more common in the aquarium trade and measures the density of a substance compared to pure water (since this “measurement” is actually a comparison, it does not have a unit of measure like “ppt” in salinity). Salinity is commonly measured using weight, chemical tests or refraction (the water’s ability to bend light waves); Specific gravity is measured using a hydrometer (a device that measures buoyancy to determine density). Marine aquariums usually have a salinity of 30-35ppt or a specific gravity of around 1.020-1.025
• Saltwater: Saltwater environments are those with a specific gravity of 1.018 or higher, or with a salinity of 30 ppt (parts per thousand) or higher. This is the environment found in oceans and seas around the world and is home to coral reefs. The term “marine” is also used to refer to anything pertaining to these environments.
• Water Hardness: Water Hardness is a measure of the amount of minerals dissolved in the water, especially Calcium and Magnesium. Like alkalinity, the water hardness affects the stability of water – the chemistry of soft water is much easier to change than hard water. Some fish like Discus or most tetras prefer soft water while others like African cichlids and Bettas thrive in hard water. Working with the hardness of your water when choosing fish and maintaining an aquarium can be far less stressful than trying to change it. Water hardness is usually measured two ways – General Hardness and Carbonate Hardness. Both are usually measured using liquid test kits and a method called “titration” – adding small amounts of solvent to a solution until and endpoint like a color change is reach.
• General Hardness is usually measures in degrees (dGH or ºGH). 1 dGH is equal to 10 milligrams of calcium oxide per liter of water or 17.848 ppm. “Very soft” water is defined as 0.4 dGH, “Soft water” is 4-8 dGH, “Slightly Hard” water is 8-12 dGH, “Moderately hard” is 12-18 dGH, and “Hard” water is 18 dGH or higher.

The Carbonate Hardness (KH) is closely related to the General Hardness but is a measure only of the calcium carbonate (CaCO₃), not of the other minerals present. This is usually more important in saltwater aquariums than in freshwater since most saltwater invertebrates have skeletons or shells made up of primarily calcium carbonate. The GH and KH are usually close but can be different, depending on the minerals present.

Hi, Eileen here. There are a lot of different terms and phrases, used in reference to saltwater and freshwater aquariums alike, that may be unfamiliar to some aquarists or that you might come across in books, magazines or your local fish store like That Fish Place/ That Pet Place. I thought it might be beneficial to place a glossary of common terms as a reference. Here are some of the most common terms used in the aquarium trade that may be confusing to someone just starting out or beginning to explore the hobby. Keep in mind that they may have different meanings or may be used differently depending on the region or the aquarist you may be speaking to.

Biological terms:

• Barbel: the “whiskers” or whisker-like appendages around the face and mouth of some fish.
• Benthic: Benthic organisms live on, in, or attached to the bottom. These organisms include corals, crabs, starfish, cucumbers and worms.
• Breeding styles: There are several different breeding styles common in aquarium fish and invertebrates.
  • Livebearer: Livebearers give birth to live young that are fully or nearly fully formed and often resemble miniature adults. Guppies, swordtails and seahorses are a few well-known livebearers.
  • Mouthbrooder: Mouthbrooders hold their eggs and eventually their young in their mouths until the young are ready to live on their own. The parent holding the young often does not eat during this time. Some cichlids and saltwater cardinalfish are mouthbrooders.
  • Egg–layer: This is the breeding style that most people are familiar with. The female fish will lay a clutch of eggs and the male will fertilize the eggs after they are released. Most parents will guard their eggs during this time. Freshwater angelfish and saltwater clownfish are common egg-layers.
  • Egg–scatterer: Egg-scatterers show little to no parental care for their young and will randomly scatterer the eggs across the substrate or vegetation. They often may eat their eggs and fry if not removed from the site. Tetras, danios, and rasboras are all egg-scatterers.
  • Bubble–nesting: Gouramis and bettas are well-known bubble-nesters. The male will build a ring or nest of bubbles at the surface of the tank or plants and will defend other fish, including the female who laid the eggs, from getting close to the next.
  • Egg–burying: Annual fish like killifish will bury their eggs in muddy substrate in the wild where they remain dormant throughout the dry season and until the next rainy season. These fish are typically short-lived and only have a lifespan of one or two seasons.
• Cichlid: Cichlids (pronounced SICK-lids) are a group of fish known for being some of the most aggressive and territorial. They are native to distinct regions and many species have limited range. Cichlids are generally divided into “Old World” and “New World” groups.
  • Old World Cichlids: These cichlids are those found generally in the eastern hemisphere, most notably the African Cichlids found in the African Rift Lakes Lake Malawi, Lake Tanganyika and Lake Victoria basin. This group also includes West African, Madagascar and Asian cichlids. These are typically found in very specific water conditions and should not usually be mixed with other more docile tropical fish.
  • New World Cichlids: These are also collectively referred to as South and Central American cichlids but may also include some found in southern North America. Many are large and aggressive, but there are also dwarf species and some that are rather docile.
• Coral: Coral refers to a very large group of invertebrates in the family Cnidaria. They are very widespread in appearance, habitat, requirements and lifestyle, but are only found in saltwater environments. This group can further be dividing into LPS, SPS, and Soft Corals.
  • Large Polyp Stony Corals (LPS): These corals have hard skeletons covered with fleshy tissue that often can make the coral look like a plant or anemone. These corals are found in a variety of environments and are often not as sensitive as their SPS cousins. They feed through a combination of photosynthesis from algae in their tissue and filter feeding from the water column. This is not technically a scientific classification, but is used by hobbyists as a convenient way of dividing corals.
  • Small Polyp Stony Corals (SPS): These corals have a more rigid appearance with very small polyps or thin tissue covering their skeletons. They live primarily on reefs and most get the majority of their nutrition from the algae in their tissue. These corals are very popular amongst hobbyists for propogation and “fragging”. Again, like LPS corals, this is not an official scientific classification.
  • Soft Corals: Also known as leather corals, the vast majority of these do not have a rigid skeleton, though there are a few exceptions, like Heliopora. They filter-feed or absorb most of their nutrition from the water and can live in a wide range of water conditions.
• Crustaceans: Crustaceans are a group of invertebrates characterized by their insect-like appearance, hard exoskeleton that they must “molt” or shed to grow, and segmented bodies. Common aquarium crustaceans are shrimp, crabs and lobsters.
• Cyanobacteria: Cyanobacteria (“cyano” or “slime algae”) is a bacteria commonly mistaken for algae and can be green, brown, red, black or blue. It is considered an aquarium nuisance and usually will bloom when water quality or lighting is poor. It is most common in saltwater aquariums, but can also be found in freshwater aquariums at times.
• Diet: Diet refers to what an animal will normally eat in the wild. Five main diet or feeding types are common in aquarium:
  • Herbivore: Herbivores eat plants and plant matter almost exclusively.
  • Carnivore: Carnivores are meat-eaters and feed on very little plant matter.
  • Omnivore: Omnivores eat both plants and animals in their nature diet. Some may eat more plants than meat or vice versa.
  • Planktivore: Plantkivores feed on very small plants and animals in the water column. They may actively search out this food or may filter feed by sifting through the water column and feeding on whatever they find there.
• Photosynthesis: Some invertebrates have algae known as zooxanthallae living in their tissue which produces proteins through photosynthesis. The animal then feeds off of the by-product of these symbiotic algae.
  • Diurnal: Diurnal organisms are active primarily during the day or in daylight.
• Fin types: Each fin and body region on a fish is named and the common or scientific name of the fish may refer to markings on or around these fins. Knowing the names of the fins can also help in identifying fish or diseases. Not all of these fins are found on every fish and there are several other minor fins found in some groups.
  • Dorsal: The dorsal fin runs along the back and spine of the fish. The dorsal side of the fish also refers to this top half or the region around its back. This fin is used to help stabilize the fish while swimming.
  • Pectoral: Pectoral refers to the chest of the fish or the fins on either side of the body just behind the gills. These fins are used mostly in steering the fish, but also help to propel it through the water.
  • Peduncal: The peduncal or caudal peduncle is the narrow area between the main body of the fish and the tail.
  • Pelvic: Pelvic fins are paired and are found under the pectoral fins on the lower part or “belly” of the fish. They are used to help stop or turn the fish and to move vertically through the water column. Some fish like gobies have fused pelvic fins that act like a suction cup and help fix the fish onto a surface.
  • Anal: This fin is located on the bottom of the fish just in front of the tail. It is also used to help stabilize the fish. In male livebearers, this fin is modified into the pointed gonopodium and is used to fertilize the female.
• Invertebrate: An invertebrate is any animal without a backbone. This group includes snails, shrimp, crabs, corals, octopuses, clams, starfish, urchins and many more animals.
• Lateral Line: The Lateral Line is a sensory organ found primarily in fish. The Lateral Line can be seen as a groove running the length of the body on most fish and is used to detect movement in the water, even from great distances. Schooling behaviors and the quick movement and reflexes seen in some fish are thought to be related to this organ. Some fish can be identified by markings around the Lateral Line and some diseases like Head and Lateral Line Erosion (HLLE) are associated with it as well.
• Nematocyst: Nematocysts are stinging cells found in the invertebrate phylum Cnidaria (anemones, jellyfish, corals and other invertebrates). The cell is “spring-loaded” – when the trigger is activated, the cell springs open and injects a harpoon-like projection into the target. This is a defense in most animals but some fish like jellyfish use this as a passive way to catch and disable their prey.
• Nocturnal: Nocturnal organisms are active primarily at night.
• Operculum: Operculum is Latin for “little lid”. In fish, this is the bony plate that covers the gills. In snails, this is the hard trapdoor that protects that snail when it retracts into its shell.
• Plankton: Plankton and planktonic organisms do not swim against the flow of the water but rather travel with the flow. Most plankton is very tiny and is a primary food of filter-feeding organisms like corals and feather dusters, but other planktonic organisms like jellyfish and even the very large Ocean Sunfish can be much larger in size.
• Photoperiod: The photoperiod is the length of day and night an organisms is exposed to and their reaction to it. An improper photoperiod can affect the health and activity of aquarium fish, invertebrates and plants.
• Photosynthesis: Photosynthesis is the process by which a plant (including algae) uses carbon dioxide and sunlight to produce organics like sugars and gives off oxygen as a by-product. Some bacteria like cyanobacteria also use photosynthesis.
• Scales: Most fish are covered with rigid scales for protection. These scales vary with the type of fish. Fish like sharks have scales also known as “dermal denticles” for their tooth-like structure. Other fish have scales with either a smooth outer edge (cycloid), or scales with a serrated edge (ctenoid).
• Scientific name: The scientific name of an organism is the name assigned to it by scientists and taxonomists to be used as the “official” and universal name for that organism. In contrast, the common name can vary between countries, languages, regions and from aquarist to aquarists. Scientific names are typically written in italics while common names are often written with quotation marks.
• Sexual Dimorphism: Sexually dimorphic animals have physical characteristics that differentiate between males and females of the same species. The difference can be subtle (a specific marking or size difference) or very obvious (completely different coloration).
• Venomous: A venomous organism injects a toxin into its prey, either as a defense or as a way to disable their prey. This differs from poisonous organisms whose toxin must be ingested or absorbed.
• Zooxanthallae: These tiny algae cells live within the tissue of other organisms like corals and anemones. The larger animals or colony provides the zooxanthallae with a host and the zooxanthallae provides the host animal with energy from photosynthesis. A coral may “bleach” or eject all of the zooxanthallae from its tissue if stressed, often resulting in the death of the coral.

I’ll be back with some other terms that may be useful for those who are new to the hobby in future posts!

In past blogs (here and here), we’ve gone over the basics of the Latin scientific naming system. Now, with spring and pond season just around the corner, it’s time to discuss a different naming system – Japanese Koi Nomenclature. Koi are considered some of the most valuable ornamental fish in some parts of the world and mature show quality koi can sell for hundreds or even thousands of dollars much like purebreed dogs and horses. Though other countries raise and produce koi, a Japanese emperor was believed to be the first to begin the practice of keeping koi in ornamental ponds and led to the breeding traditions practiced today. Koi are still usually referred to by their Japanese names for color and pattern.

Like the Latin naming system, the color of the fish plays a large part in the naming system and can point to more specific details in a larger group. For example, Bekko koi are fish that have black markings on a white, red or yellow background. Ki Bekko koi refer to those with a yellow background (“Ki” = “yellow”). The term “hikari” in koi names is also used to refer to a metallic sheen to the scales. Some color terms commonly used for koi are:

The most common Japanese terms that are used in reference to koi are those that refer to the pattern on the fish. The most common varieties are Kohaku, Sanke and Showa but there are over 15 commonly-used varieties and each of these can be broken down farther into color variations within that pattern or through lines developed by various breeders.  Some of the most common varieties are:

• Kohaku – Kohaku koi are white with red markings. High quality Kohaku are pure white with no yellow in the coloring and have a deep, solid red color in the markings.
• Sanke – Sanke is one of the most popular varieties. Like the Kohaku, these koi are white with red markings, but Sanke koi also have black markings superimposed on the red and white. High quality Sanke may not be symmetrical in their coloration, but the color should be distributed over the entire body, except for the head.
• Showa – Showa koi are very similar to Sanke but can have much more black on their bodies. The black can be anywhere on the body, including the head, sides and belly (considered undesireable for Sanke koi). Hi Showa is an example of a subvariety of the Showa koi with more deep red color than others.
• Asagi – Asagi koi are one of the most distinctive varieties (and my personal favorite). These koi have blue bodies, white heads and red markings in the tail, fins and face.
• Bekko – These koi have black markings with a white, red or yellow base color. The name of the color is usually used to determine which type of Bekko a fish is (Aka Bekko, Ki Bekko, or Shiro Bekko).
• Goshiki – “Goshiki” literally means “5-colored”, in this case light blue, dark blue, red, black and white. The markings are colored over a white background. This variety can be highly variable in appearance.
• Hikari Utsuri – These koi have the same pattern as Showa and Utsuri koi, but have a metallic sheen to their scales.
• Hikarimoyo – These koi are also metallic but are made up of the metallic koi that are not Showa or Utsuri. Hariwake is a popular variety within this group; this subvariety is metallic silver with orange or yellow markings.
• Hikarimuji – Hikarimuji is another metallic variety but these fish are all one solid metallic color. Pure-colored metallic koi within this category are also known as Ogon koi, leading to the popular Yamabuki Ogons (pale metallic yellow) and Platinum Ogons (pure white and metallic).
• Kawarimono – This variety is like the Hikarimoyo variety in that it included all fish not included in the other popular varieties, but koi within this group can also be divided into their out categories describing their breeder lineage, color or scale traits. The terms “Gin Rin” (meaning sparkling scales) and “Doitsu” (referring to fish that are otherwise scaleless except for mirrored scales around the dorsal fin) are used more in this variety than most others.
• Koromo – Koromo koi are similar to Kohaku, but the scales of the red pattern in Koromo koi have dark edges, leading to an almost crosshatched pattern on these markings.
• Tancho – Tancho koi can sometimes fit within the Kohaku, Sanke or Showa categories, but the markings in Tancho koi are more specific. Tancho koi are white with one red patch on their head, preferably as circular as possible. Tancho Kohaku are the most popular with their pure white bodies and one red patch, but Tancho Sanke and Tancho Showa koi are also popular.
• Utsurimono or Utsuri – These koi are in some ways the opposite of Bekko koi. Instead of having black marings on a colored background, Utsuri koi are black with white, red or yellow markings. Shiro Utsuri, the black and white variety, are the most common, folowed by the more rare Hi Utsuri (red and black) and Ki Utsuri (yellow and black).

This list is far from all-inclusive of all the koi varieties and patterns but can give you a good start in learning the difference between all of the varieties available. As this list demonstrates, koi are some of the most collectible and carefully-bred fish around with a history going back hundreds of years. Koi and pond care can open up a whole new frontier for avid aquarists and the time to start planning your new pond or new pond additions is here! Chart referenced from Wikipedia here.

Seahorses have long been one of the icons of the aquarium hobby, with graceful movements and a delicate, unusual appearance. Seahorses are members of a family of fish known as Sygnathids, meaning “spiny-finned fish”. Other members of the family include Sea Dragons and Pipefish. They each have a small tubular snout that enables them to suck in prey items like brine shrimp, copepods, and other similar crustaceans. Seahorses and their relatives are timid and slow-moving. They are most often found in beds or sea grass where they can use their tails to anchor themselves to the grass or corals and not be carried off by the current. Seahorses bear live young that are carried in a pouch, similar to a Kangaroo, until they are mature enough to be released.

A couple of years ago, seahorses were a rather common offering in Aquarium Stores nationwide. Seahorses have long been one of the icons of the aquarium hobby, with graceful movements and a delicate, unusual appearance. In recent years, the with the technical advancements in aquarium keeping, environments can be created to more easily and better suited to keeping these amazing fish. The possibility of keeping sea horses is more within reach than ever. But where have they gone?

In 2004, the Convention on International Trade in Endangered Species (CITES) upgraded the status of Seahorse species to “vulnerable” meaning that the seahorse populations are in danger of a 30% decrease due to targeted catch, accidental capture, and habitat loss. One of the biggest threats to these species is the high demand for their dried bodies in Asian and Southeast Asian medicine trades. Climate changes and habitat destruction are also taking huge tolls on these interesting and amazing little creatures.

With growing awareness and increased conservation efforts, captive breeding programs for these animals are growing in number and are becoming increasingly successful. If you’re lucky enough to venture into keeping them in a home aquarium, strive to purchase captive raised individuals. By doing so, stress on wild populations can be reduced, and these animals tend to adapt to aquarium conditions and diets with more ease than wild-caught specimens. Be sure to check out the related articles in the blog for more fascinating facts and tips on keeping these guys at home.

Thanks, Eileen