Common Corydoradine Catfish (Helmet Skin Catfish) First Edition A guide to the care, feeding, breeding and raising Of Common Corydoras Species By James Studdart BSc (Hons) Contents -Acknowledgements -About Corydoras - Corys at home -The Tank Setup -Company of their own - Tank mates - The Tank - Planted Cory Tank -Feeding -Common Species Identification - C. Aeneus (Bronze Cory) - C. Sterbai (Sterbai's Cory) - C. Paleatus (Peppered Cory) - C. Trilineatus (Three Line Cory) - The Albino Cory: Not a single species -Breeding - Sexing - Preparation -From Eggs to Fry - Eggs - What to do when you get eggs - Tank Setup - Fry - Tank Setup -Feeding - Micro Worms - Pre-made foods - Growing out -References -Bibliography Acknowledgements I would like to thank the following people for their help, and their generosity. My thanks go directly to planetcatfish.com for granting permission for the use of their website for information, and the use of their images. The following people and organisations are also to be thanked: • Tropical Fish Forums – www.fishforums.net • Inchworm of Tropical Fish Forums • Carmen Webb – for providing the Microworm Article, photos and my starter culture And any other people who I have not mentioned here but helped me in my quest to produce this documentation. About Corydoras These fish are members of a South American catfish genus known as Corydoras. Corydora are freshwater temperate and tropical catfish in the armoured catfish family, and are commonly referred to as Corys. The type species for this genus is Corydoras Geoffrey. The name Corydoras is derived from the Greek kory (helmet) and doras (skin). Corydoras is has over 180 described species, many variants exist as well, including colour morphs and long fins varieties, plus several hundred Corydoras species are not yet classified, but kept by aquarists. These species are given C- Numbers, similar to the L numbers given the Plecs. The C-Number categorisation was originally devised by Hans-Georg Evers for the German fish keeping magazine DATZ in 1993. As of 2006, there are 153 C-numbers assigned, of which 32 have subsequently been assigned appropriate scientific names. Corydoras are native to slow-moving and almost still streams and small rivers of South America where the water is shallow and very clear. The preferred bottom seems to be sand or sand mixed with mud, sometimes covered with detritus or dead leaves. The banks and sides of the streams are covered with a dense growth of plants, and this is where the Corys are found. They inhabit a wide variety of water types but tend they are documented to prefer soft, neutral to slightly acidic water. They can tolerate only a small amount of salt (some species tolerate none at all), although it is not recommended to add salt to their water. Many species are found in schools or aggregations of hundreds or even thousands of individuals, usually of a single species, but occasionally with other species mixed in. Their main food sources are normally, bottom-dwelling insects and insect larvae and various worms, they also consume some vegetable matter. Corydora were once thought to kill other tank mates and then feed upon them, although this is now known to be a false view. Corydora are not piscivoures, although they will eat dead fish, that the find. They feed buy sifting through the substrate, using their barbels to taste, with their snouts fully submerged in the substrate. This is why you should not use gravel as substrate for a tank with Corys, as they will wear down their barbels, which causes problems for the fish, and leaves it open to infection. Scientific classification Class: Actinopterygii Order: Siluriformes Family: Callichthyidae Genus: Corydoras Corys At home Corys are popular aquarium fish and typically measure around four to seven centimetres in length. They are well suited to tropical freshwater community aquariums, as they get along well with other species and are not at all aggressive. Corys are shy fish and it is recommended to keep them in groups of at least six as most species seem to form shoals in the aquaria. These are easy fish to keep, being peaceful, small, hardy, active, and entertaining. Occasionally they will swim to the surface of the tank, to gulp air, they are not breathing the atmospheric air, like beta's and gourami, but they use the air to help their digestion. Corydoras are very good choices for a community aquarium, and are widely kept throughout the world. These fish have a long lifespan; A C. Aeneus is said to have for lived 27 years in captivity, although 20 years is not too uncommon. There are four species commonly found in aquarium retailers, which we will discuss in this article, these are: - C. Aeneus (Bronze Cory) - C. Sterbai (Sterbai's Cory) - C. Paleatus (Peppered Cory) - C. Trilineatus (Three Line Cory) Some of these species are also available in albino form (See The Albino Cory: Not a single species, Pg. X) and Long fin varieties. Unfortunately these fish are just one of thousands of species to be involved in the act of dying, this is a process with fish are artificially coloured. the latest trend is known as "Tattooing" where fish are available with comments such as "I LOVE YOU!" and such on their flanks. This is painful for the fish and can also harm the fish physically as well as mentally. Many retailers have signed up to Practical Fish Keeping's movement to stop this act, and there have been laws passed to stop this in the UK and many other countries, although the import of dyed fish is still not outlawed, and in the eyes of many fish keepers, professional, amateur and beginner should be stopped with immediate effect, so please if you see a dyed fish (See Figure 1.0), not just corys do not buy them, if their is no demand for them the companies doing this wont produce them any more. Figure 1.0 - Artificially Dyed Corydora Aeneus There are a number of species of other South American Catfish that is commonly mistaken for Corydoras, there are: - Aspidoras - Brochis - Scleromystax They are very similar to Corydora, although these tend to grow a lot larger than Corydoras, there are other distinguishing features with the other species that defines them as such, but this document will concentrate on only Corydoras. The Tank Setup Company of their own As said earlier Corydoras do best in groups, they can be kept in groups of mixed species, but they prefer the company of their own. I shoal of 6 or more is usually suggested by many aquarists, although some have managed to keep and spawn them in groups of as small as two. Corydoras are peaceful fish, as well as very shy, keeping them in a group will help their confidence as well. Tank mates When considering tank mates for your Corydoras you will not want any boisterous fish, such as sharks or Cichlids, nor should they be kept with too many other bottom-dwelling fish, as this could cause too much competition for food, and being a shy fish, the Corys would probably retreat when challenged by another fish, and therefore starve. Suitable tank mates include small loaches, such as the Chain Loach (Yasuhikotakia Sidthimunki, formerly Botia Sidthimunki), Tetras, such as neons (Paracheirodon innesi), Xray (Pristella maxillaris), black phantom (Megalamphodus megalopterus) or caridnal (Paracheirodon axelrodi). You will find other species such as small plec species will also fair well with Corydoras. Basically any small, non-aggressive or boisterous fish would suit a Corydora setup. If you are looking at breeding your Corydoras I personally would suggest a species tank, although some species will readily spawn in a community tank. In the community the eggs are hard to find, and will also be eaten by other fish. The Tank With all bottom-dwelling fish it is the foot print of the tank not the height tank that is important, so the large the foot print the move fish. Corydoras do not create vast amounts of waste, like that seen from bristlenose plecs for instance, so light filtration will be fine. Substrate should be sand, to enable the Corydoras to forage without damaging their barbels. You can safely keep a shoal of eight, fully grown, Corydora in a 15 gallon (17 US gallon) tank, with the dimensions of 24" x 12" x 14" (See below for the tank specifications). As for decorations, bog wood, monapi wood or large rounded river stones would suit best giving the aesthetic look of a natural environment. Ensure you have soaked you wood, both bog and monapi leech tannin into the water, this discolours the water as well as effects the PH, as the tannin is acidic. Also make sure the stones you use do not contain any minerals such as lime, to test this you can place a few drops of malt vinegar on the stones, if they fizz they are unsuitable, but if you purchased them from a aquatics shop they should be ok to use. As for lighting, standard tank lighting will be fine, unless you are considering plants, then you will need brighter and more efficient lighting. Tank Specifications: Dimensions: 61 x 30 x 36cm/24" x 12" x 14" Surface area: 0.18 sqm/1.94 sq ft/ inches sq in Volume: 66 l./15 gal. (17.44 US gal.) Probable volume: 59 l./14 gal. (16 US gal.) Stocking density: 14"/36cm (built up gradually) Maximum density: 28"/71cm (theoretical maximum) (Specification provided by www.practicalfishkeeping.co.uk) Planted Cory Tanks If you want to try a planted Cory tank, you will be better advised to you large leaves plants such as the Amazon Swords (Echinodorus amazonicus) and other such plants. You do not want to use a plant that will cover the floor of the tank, as this is irritate your Corys, and they will not be able forage efficiently causing unrequited stress. Large leaved plants also give the Corys some place to stick their eggs to when spawning, although most of the eggs will be probably placed in the glass. Keep in mind NOT ALL Corys spawn in this way. If you do decide to breed you Corys in a planted tank, you will find it hard to find the eggs, and removal is even harder. Feeding Corydora are omnivores, which means they feed on both plant and animal matter, they do require protein, which is more often than not over looked by the aquarist, who on some occasions treat them as 'Cleaning' fish. It is true these fish are scavengers, but they have more nutritional needs than just scraps that are not eaten by the other fish. Corys will take any foods, from dried flake food and catfish pellets to bloodworm and other insects, frozen or other wise. You can buy freeze dried bloodworm and tubiflex worms, but I would advise against using these, mainly because they have lost most of their nutritional values, and float, so the Corys wont eat them. They then break down and ad to the waste in the tank, thus increase the nitrate, nitrite and ammonia levels in the water. Although feeding living and frozen bloodworm and such like insects is great for the fish, you should only feed these to them every other day, and supplement their diets with vegetable matter. On alternative days feed them dried pellets or tablets, such asTetra: Tabimin, or King British: Cat Fish pellets. A well balanced and varied diet is key to the health and longevity of any fish. Figure 3.0 - Suggest Food for Corydoras [FOOD!!] You can buy live foods from aquatic shops, but it is cheaper to grow your own cultures of live foods. Either that or buy frozen foods, which now come in handy blister packs, with a single serving providing enough food for at least 3- 4 tanks of Corys. Live cultures for bloodworm are hard to maintain, as bloodworm is the larval stage of midges, a small flying insect. You have to maintain a population of adults to lay their eggs and hatch them into the worms. In my opinion it is a lot cheaper and easier to buy frozen bloodworms. Common Species Identification The following Section will help to identify your Corydora, as many of the species get confused with each other. Some other following have different colour morphs, and fin shapes, the ‘normal’ strain are shown here, for the albino strains please see The Albino Cory: Not a single species. Corydoras Aeneus Common names: Bronze Cory Distribution: Trinidad, Venezuela, La Plata Length: 2.8” Water Temperature: 19-26oC Description: This is amongst the most frequently, and there is the most common of the Corydoras found in aquatic stores. The body shape is arched, with the forehead rising quite steeply from a down-turned mouth, around which are three pairs of barbels. The flanks are bronze coloured with a darker area immediately behind the gill cover which tapers to a point level with the rear end of the dorsal fin. These fish are actually sub-tropical fish; unlike many of the other members of its family it prefers lower temperatures. Figure 4.1 – C. Aeneus Variants: · Black · Red/Orange Laser · Green Laser · Gold Stripe · Gold · Green · Albino · Long Fin Corydoras Sterbai Common names: Sterbai’s Cory Distribution: Brazil Length: 2.6” Water Temperature: 24.0-28.0oC Description: It is hard to misidentify this species but it can be confused with Corydoras Haraldschultzi, although the latter is a long nosed species where C. Sterbai is the dome headed form - the easiest way to tell them apart is that the Sterbai’s Cory has white spots on its head from eyes down to snout. C. Haraldschultzi does not. Corydoras Sterbai has recently become available in albino form. Figure 4.2 – C. Sterbai Variants: · Albino Corydoras Paleatus Common names: Peppered Cory Distribution: Guyana Length: 2.4” Water Temperature: 19-26oC Description: Adults are easily identified but young can be confused with some other Corydoras (such as C. Barbatus and the like) or even young Aspidoras. Wild caught individuals look quite different from farm raised fish commonly encountered for sale. Wild fish have a higher contrast pattern, the pigmentation shimmers like foil in natural sunlight. Females grow considerably larger and possess a heavier girth when sexually mature (See Figure 4.4). Egg-ripe females can get so robust that the fish cannot lie flat against the substrate! The size difference in sexes is illustrated clearly in the images below. These fish are actually sub-tropical fish; unlike many of the other members of its family it prefers lower temperatures. Figure 4.3 – C. Paleatus - Male Figure 4.4 – C. Paleatus - Female Variants: · Albino · Long Fin Corydoras Trilineatus Common names: Three Line Cory Distribution: Peruvian Amazon: Rio Ampiyacu, Rio Ucayali and the Yarina Cocha. Ecuador: Rio Pastaza. Length: 2.8” Water Temperature: 16-25oC Description: Probably the most misidentified fish commonly found in aquatic retailers who incorrectly sell it as C. Julii. The true C. Julii is such a rare import that sheer numbers means you are unlikely to really encounter this Brazilian fish. C. Julii is similar to the more spotted forms of C. Trilineatus but has no trace of any reticulated colour patterning at all and is entirely covered with small, distinct spots. Its mid-lateral black stripe is fainter and does not reach as far towards the fishes head as in C. Trilineatus Figure 4.5 – C. Trilineatus - Male Variants: · Spotted – Similar to the C. Julii Albino: Not a single Species Figure 4.6 – C. Sterbai - Albino Figure 4.7 – C. Aeneus - Albino Figure 4.8 – C. Paleatus - Albino Breeding Sexing "Males are smaller and slimmer. Females grow larger and are much wider which can most easily be observed from above." - www.Planetcatfish.com Figure 5.0 - Sexing Corydoras As you can see from the illustration above females, are larger than the males, they also tend to be taller as well. As stated by Planetcatfish.com a good way to sex Corys is front above, females tend to be rounder and plumper behind the pectoral fins (See Figure 5.0), this is exaggerated when the fish is full of eggs. If your fish are young, the sexual differences are not as apparent, another way is to look at their Ventral fins. Males ten to have longer pointed Ventral fins, where as females have rounder fins, this is an adaptation as the females clasp 1-4 eggs at time during spawning between these fins, while looking for a place to put them. Preparation When you have your tank setup any running and your Corys have settled in, you can start to prep them for spawning. Depending on what you have been feeding them, you will want to start feeding more live or frozen bloodworms, or other such foods, less of the dried foods, and more of meaty food. Change between 25-50% of the water in the tank with cold water, this will drop the tank temp down by several degrees. This simulates the raining season, in which the Corys spawn in the wild. I also drop the thermostat down to about 2324* C (74-76*F) creating an over all cooler tank setup. You should notice that over the next week the female will plump up and become apparently fat. The males will start to chase the females. You will notice the females start cleaning the tank walls; this is in preparation for the eggs. From Egg to Fry In this section will we look at the collection, and care for the eggs, and also the feeding, caring and ‘growing out’ of the fry. Eggs Figure 6.1.1 – A Cory egg on a leaf Once your Corys have laid their eggs, you will want to either remove the eggs or the parents. It is seen as a better option to remove the eggs from the parent’s tank, where the eggs can be hatched under 'clean' conditions. Depending on what method you choose, you may remove the eggs to separate tank. I use a 3 gallon tank to hatch the eggs in; the water is set to around 26oC. The warmer temperature helps quicker developments of the eggs. To remove the eggs there are two ways which are widely used, these are known as "The Roll Method" and "The Razor blade method" The Roll Method Apply a slight pressure to the egg, be careful as they will burst. and push the egg up the glass, it should come away from the glass and be stuck to your finger. Now push the egg gently, again, against the glass in the hatching tank, and roll you finger down, the eggs should still be sticky and it should stick to the glass. The Razor Blade Method Use a razor blade to scrape the eggs from the glass of the spawning tank and then place the eggs on the glass as stated above in "The Roll Method" The Tank The eggs are very susceptible to fungus infections so to help prevent these, you will need to add some Methylene blue to the water, be careful as this will stain EVERYTHING. You will also need to add an air stone, this ensure the water in the tank is continuously moving. This will help the fry when they hatch to reach the surface to fill their swim-bladders with air. Fry The Tank Setup There are many techniques used for fry tanks, but the one we will focus on here is the bare bottom method. Bare bottom Method You will need a small tank of between 2-5 gallons, depending on the number of fry. The Tank will be completely empty, apart from a sponge filter and the heater. Keep the water temp quiet high, around 26oC. In high temps, the fry will eat more and grow quicker. You will want run a small air-stone for the first few days of the fry’s lives; this will keep the water oxygenated, the water moving and also helps the fry to reach the surface for air. On about day 3-4 you want to install your sponge filter, Huey Hung produces a small sponge filter which is excellent for fry tanks, and they run nearly silent, depending on your air pump. Every day, change between 20-50% of the water, as clean water is essential for the first few months. You can make up a bucket of water and use that so the water will be room temperature, as sudden drops or rises in temperature will cause the fry to die. Make sure you clean the sides and floor of the tank as well, as the fry are very susceptible to bacterial infections and fungus. The feeding of your fish should be done between 2-4 times a day, depending on what you are able to do, if you are feeding microworms you can add a large amount each time and get away with only two feeds a day, as the worms will live for about 48hours under water. Over the next few months the fry will grow rapidly and will need to be moved to a bigger tank, after about 3 months the growth rate will slow. After about 3-4months the fry should be about 1”-1.5” in total length and will be ready to move into your community or Cory tank. They are also now large enough for aquatic shops to buy and sell on. You maybe able to get store credit or cash for the fish, but don’t just turn up with the fish and demand they take them. Your best method would to be contact the retailer first, and find out if they are willing to take the fish off your hands. Feeding Microworms – By Carmen Webb You want to make this as soon as the eggs are laid as t will take a few days for the culture to become ready; I make a new culture every 4 -5 days. You can feed them to all your fish; they all go absolutely mad for them, especially the Corys. Although some large fish will ignore the worms, they will be eaten by small tetra and other small fish. Required Items: • Two containers Large margarine tubs will work fine, or the tubs you buy for holding food stuffs, which are easily bought from a supermarket. • Ready Brek or some form of prepared breakfast oats, not Scottish oats. • Dried Yeast • Micro worm Culture Available from some aquatic retailers, or from the internet. 1. Pour a splash of room temp water in a cup and add 1 teaspoon yeast. I normally leave mine to dissolve properly, about 5 minutes. Figure 6.2.1 – Yeast & Water 2. Then add 5-6 tablespoons of the ready brek and stir. You'll need to add some more room temp water till the mixture is thick, but not roll into balls, just slides off the spoon. Figure 6.2.2 – The mixture 3. Spread evenly on the bottom of your tub, try avoiding the sides. Add the microworms and mix them in gently. If you need to add a bit more water to make it easier, then do so. But don't add too much, you don't want it runny. Figure 6.2.3 – Mixture in Tub 4. Once that's all done, place the lid on the tub and store it where ever you plan on keeping them. Make sure you have punched holes in the lid before hand. I just use the scissors; you don't want them to be gaping holes, just big enough to allow air in the tub. Figure 6.2.4 – Add the Starter Culture to the mix 5. After a couple of days, you should see them climbing up the sides of the tub. I use a wooden skewer to wipe them off and feed to my fry. Don't get any oat mix on the stick, just worms. Pre-Made Foods There are a few pre-made foods for fry on the market currently, from crushed flakes for livebearers and liquid food for egg layers. As we are talking about Corys we will need the Liquid food for egg layers. Interpet make a product called Liqui-Fry No1, which is designed specifically for egg layers. This comes with instructions, although most breeders don’t use pre-made foods as they don’t provide the full nutrition that fry need. Most Breeders will suggest you use Microworms, which how to create a culture of these has been shown above, or vinegar eels.