Keeping Mudskippers Contents Introduction to Mudskippers (1.1) Species - The commonly traded genera (1.2) Choosing the best specimen in-store (1.3) Habitat Setup and maintainability (1.4) Planting a Brackish tank, to make a Paludarium (1.5) Feeding (1.6) Sources (1.7) Often Confusing Terms Explained (1.8) Please hit Control F, then type the number needed on your keyboard, to search through. I'd like to apologize in advance before I start this article; A) It's roughly 5 to 7 A4 pages long. B) It's in really poor taste that I have no published book sources. C) My old college tutors would give me a big ol' slap for not properly using the Harvard system of referencing. As it's an online public and free to use article, I'm just going to list the websites instead of the full system. Introduction to Mudskippers (1.1) Let's get started; Mudskippers are members of the family Gobiidae (Gobies). There are numerous genera of the Mudskipper species that live in different areas around the world, they live in brackish water conditions. I'm going to concentrate on the Periophthalmus genus. These amphibious fish are typically found living in mangrove swamps, lagoons and are also comfortable along muddy estuaries. They are found living in the wild in tropical, subtropical and temperate regions, including the Indo-Pacific and the Atlantic coast of Africa. They are fairly inquisitive fish, often in aquariums they can be found at the front of the tank, staring into the room with their impressive 360° vision. All Mudskippers are territorial, although the degree of aggression varies genus to genus and also fish to fish. The larger species are said to be often so aggressive that they cannot be maintained in groups, under home aquarium conditions and thus best kept alone. Of course this is entirely dependent on the individual fishes temperament. For instance, I keep two west African/Atlantic (Periophthalmus barbarus) and they're fine together, with the occasional spat they stay out of each others eye line. Please do not keep different genera of Mudskipper together, the larger will probably hurt, kill or bully the smaller. Also do not keep Mudskippers with any other fish, amphibian, crustacean or invertebrate, they must be kept absolutely separate. These fish have special anatomical and behavioral adaptations to allow them to be amphibious, which allows these fish the ability to spend up to 90% of their time, out of the water. This family has evolved it's pectoral fins into basic legs, allowing them the ability to 'skip' along the substrate. As well as evolved pelvic fins, providing stability under the fish's crude legs. However, please do not be fooled into thinking that these fish are slow and sluggish, they can move quite rapidly and even jump, if the need arises, due to their tail that provides a propelling momentum. Also the way this species respires is quite ingenious, they employ two methods of respiration. The first being cutaneous air breathing, which unfortunately forces the Mudskippers to keep their skin moist for them to be able to respire. They also have enlarged gill chambers (opercula), where they retain an air bubble. You will be able to see that as they rotate their eyes, pressure is applied to the opercula cavity and this re-oxygenates the stored water, lubricates the gill flaps and restores the gills to their normal function. A rather unusual aspect of Mudskippers, is that they are one of the few fishes that can actually drown! They need to be able to poke their heads above the water's surface, but more head room should be provided. This species has to thermo-regulate, thus they are often seen digging tunnels in soft but stable substrate and ejecting the substrate around the entrance to the tunnel, these tunnels also help them to stay away from predators, sleep, lay their eggs and provides shelter during high tides. Mudskippers are hardy fish, more tolerant of poor water conditions, when you consider their natural habitat. However this higher tolerance to nitrate does not mean that they do not require filtration and is no excuse for poor fish-keeping, it just means water changes can be slightly less frequent if necessary. Lastly, these fish can but will not breed in captivity and will live for approximately 5 years with good fish keeping. Species - The commonly traded genera (1.2) I'd prefer to concentrate on the main three commonly traded Periophthalmus, specifically the Dwarf Indian Mudskipper (Periophthalmus novemradiatus), African/Atlantic Mudskipper, (Periophthalmus barbarus) and finally the Silver-barred Mudskippers (Periophthalmus argentilineatus). Periophthalmus novemradiatus (Dwarf Indian Mudskipper) Periophthalmus novemradiatus is thought to be the smallest species in the genus, the largest recorded measured only 2.6" (6.4cm). This small species has yellow dorsal fins with red and white spots. Both fins are edged with black bands, the front dorsal fin also has a large orange blotch. This genus prefers a pH of between 7.0 – 8.5, a hardness of 10 – 25°H, specific gravity of 1.005 and temperature ranging between 25°C - 30°C (77°F - 86°F) with a high humidity, thus best kept within a lidded tank. Periophthalmus barbarus (West African / Atlantic Mudskipper) The largest recorded in captivity is around 6" (15cm) but in the wild has been known to reach 10" (25.4cm). Known as the more aggressive genus of Mudskipper, special care and consideration should be given as to preventing or dealing with aggression. Periophthalmus barbarus can be recognized not just by its large size but also by its two navy blue dorsal fins both edged with electric blue bands, unfortunately it is also mis-advertised as a similar species known as Periophthalmodon septemradiatus. As with the Dwarf Indian Mudskipper, the barbarus prefers a pH of 7.0 – 8.5, a hardness of 10 – 25°H, a specific gravity of 1.005 and the temperature of 25°C - 30°C (77°F – 86°F), again with high humidity. Periophthalmus argentilineatus (Silver-barred Mudskippers) The Silver-barred Mudskipper is approximately 8" (20cm) and thus the largest of the commonly traded Mudskippers. Thankfully, this genus isn’t nearly as aggressive as Periophthalmus barbarus. They can be recognized by the silvery vertical stripes along the flanks. The dorsal fins are brown with silvery spots, edged with thick black and narrow white bands. As with the Dwarf Indian Mudskipper and the African / Atlantic Mudskipper, the Silver-barred Mudskipper prefers a pH of 7.0 – 8.5, a hardness of 10 – 25°H, a specific gravity of 1.005 and the temperature of 25°C - 30°C (77°F – 86°F), yet again with high humidity. Choosing the best specimen in-store (1.3) So you've found a 'LFS' that supplies Mudskippers, but you don't know which to get? Look for the Mudskipper of the genus you want with the brightest pigmentation, this will indicate that it's had a healthy diet and isn't too stressed. Check for physical damage, healed wounds, signs of stress or infection and if there is any, do not buy them. You could even alert your LFS to the state of the problematic Mudskippers, so they can be moved to another tank before they are bullied to death. Find the Mudskipper with the strongest looking dorsal fin (back) and evenly spread pelvic fin (underneath) and with the best symmetry in tail size, equivalent to it's body. Be sure to ask how long this batch has been in the store and what it's approximate age is and then mentally factor in that they live approximately 5 years total. If your 'LFS' is selling different genera Mudskippers together in the same enclosure, please inform them of their error and request that the store separate them by genus for the sake of the fish, perhaps mention that they'll make a loss in profit when all the smaller ones mysteriously keep ending up dead. They'll probably already be grossly overstocked, why allow them to add insult to injury. So, please check again later as to whether they have complied with your request, if they haven't, I guess it's time to name and shame? Habitat Setup and maintainability (1.4) As always, design is completely of your choice. During research you will find that many different sources suggest larger and larger tanks per one Mudskipper. I personally keep two barbarus in a 2ft tank, 25% of the volume of the tank is water in the form of a central lake, surrounded by land. However they're perfectly adapted to a 50/50 set up as well, which most keepers will have them in. Keep in mind when buying these oddball fish, you must always buy them on the basis that your tank, will and always will be your pets permanent home, so you have to have enough room for the full sized fish. For inspiration, I suggest viewing the Photobucket pictures in my signature. It's all about personal taste, this taste is mine. Although I still need to get some brackish plants in there as I'm not comfortable with the bare sand aesthetic. Maintenance is as easy or as difficult as you'd like to make it. I'd recommend regularly washing any sponge media filter with previously siphoned brackish water from the tank to remove large debris as well as general grime. This will keep those vital bacteria within your sponge. Invest in a siphon gravel cleaning tube to remove things like carcasses, uneaten flake and any other bio-matter. If using a sand substrate, stir up the sand and wait for the heavier particles to settle, then siphon about an inch above the sand. Please remember you will need to calculate how much marine salt to reintroduce when doing a water change. Water changes should be 10% of the total water volume weekly, or 15% of the total water volume if using less than 25% total volume of water, just to be on the safe side. You may notice, if you've set up a tank where the drift wood is exposed to air, white fluffy mold/bacteria growing on your drift wood. This is temporary and common with drift wood, especially if it has been fully submerged, then left to dry, then placed back in a tank. It will not hurt your Mudskippers, but you may want to take a knife and scrape off the mold regularly until it stops coming back, as it is unsightly. You will need; Heater – Fully submersible heater is fine, please use a foam cover or aquarium safe plastic tubing, as Mudskippers enjoy laying on heaters, but unfortunately it can burn them! You can also use a stick on heated mat, often used for reptiles. It must only cover 1/4 to 1/2 of the tank as Mudskippers thermo-regulate, so they'll move to the other side of the tank to cool down. It needs to be placed on the bottom of the tank on the outside, elevate the tank with some foam pads that should be supplied to allow air flow. The downside to this is you may have to buy an expensive thermostat to regulate the temperature if one isn't supplied with your purchase. Filter – Depending on what sort of tank you're going for, I'd recommend the small but powerful filters like the "Fluval Mini". Mudskippers are extremely messy critters, they poop a lot more than you'd expect them to, plus they don't always finish their food. Substrate – From personal experience, I would recommend going for a fine sand or sand substitute, but the sand also needs some stability so the Mudskippers can dig their tunnels. I have mixed 2 parts sand to one part fine gravel. You can create mud, I wouldn't know how, but I have been advised against this, as it would be difficult to clean and wouldn't be pretty on the eyes. Drift wood, land or turtle docks – This is an absolute MUST, it will allow you're pets to be able to 'perch' around the tank, spending 90% of their time out of the water will require you to have a lot of perching areas for these territorial fish. Please note, if you're going to invest in more than one Mudskipper, to allow numerous areas, per fish. Marine Salt – To make your freshwater brackish. Please do not use table and rock salts, they contain too many impurities for use in an Aquarium, any aquarium. Hygrometer – To check the humidity and often temperature of your tank. Refractometre or Hydrometer - To check the salinity of your tank. Warning, a refractometre can be quite expensive, personally I'm winging it, which is not good! Thermometer – To check the temperature, please check if your hygrometer has a temperature read out prior to getting a thermometer though. Water Conditioner – To remove chlorine, chloramines and heavy metals from your tap water. Tank – I must emphasize the use of a lidded tank, brackish water evaporates extremely quickly. For appropriate moisture retention and to allow gasses to escape, I have placed sponge into the ventilation gaps at the top. Gravel siphon tube - To remove large debris and to do water changes Food – Please scroll down for the section on Feeding (1.6) Planting a Brackish tank, to make a Paludarium (1.5) Please remember that this is a brackish tank, so you cannot use freshwater plants, you'll need plants that are able to tolerate salty water and higher temperatures. Your Mudskippers natural habitat is most likely mangrove swamp land and they're more than happy with mangrove. You can keep mangrove, however they can grow absolutely huge. They can be trimmed down, but only once they've reached a certain point which generally is higher than a foot, (12" / 30cm) otherwise trimming them will kill them. So I'd recommend other brackish plants, depending on the tank you want, you'll need to think about whether the plant is going to need to be fully submerged, part submerged or just root submerged in substrate. For a root submerged in substrate plants, I would recommend the Red Tiger Lotus (Nymphaea lotus). For fully submerged, I can also recommend the Dwarf Sag (Sagittaria platyphylla). You can find numerous other brackish plants here (clicky) and here (clicky). Lastly, on the subject of plants. You may need to invest in a Fluorescent grow-light. Feeding (1.6) I feed my Mudskippers with tropical fish flake, thawed bloodworm and baby black crickets. Mudskippers are opportunistic omnivores, so will eat a wide array of different foods. Try not to feed them any unhealthy human foods such as bacon, or anything too fatty. A tip I received once for what to feed them in a pinch, although I doubt anyone has any laying around, is finely shredded beef heart. I feed my Mudskippers once a day, for six days of the week, as I do with my regular fish. They eat approximately two baby black crickets each along with a pinch of flake. Please remember, they are fish, effectively walking stomachs and they don't know when to stop. I have noted in several places that over feeding Mudskippers leads to health problems. I know there is relatively little information in regards to how much to feed them, so feed them like every other fish until you've researched differently, then tell me so I can update this post. hehe Please note, for black crickets especially, you will more than likely find carcasses laying around the tank, this is effectively just the shell of the cricket, but may not be filtered properly, thus making it so that you'll have to scoop out them via a net. This should only take a couple of minutes, it also gives you time to determine what your Mudskipper is like in regards to disturbance, whether it'll be shy, aggressive or passive. Please remember, what you feed your live food, you're also feeding to your Mudskippers, this is recognized as the food chain, but also coined as gut busting. I feed my black crickets with potato scrapings, fresh lettuce but not iceberg lettuce as I was recommended against and flake. Although a quick Google will reveal the true range of food that you can feed your live food. For more information on feeding, it never hurts to ask your LFS. Mine told me that he feeds one bag of live bloodworm for a tank of (insanely overstocked) 20 Mudskippers. Sources (1.7) http://www.google.co.uk http://en.wikipedia.org/wiki/Mudskipper#Species http://www.vexen.co.uk/holy****/mudskipper.html http://homepage.mac.com/nmonks/Projects/FAQ/5c.html http://www.algone.com/aquarium-articles/saltwater-aquarium/saltwater-salinity http://www.seriouslyfish.com/profile.php?genus=Periophthalmus&species=novemradiatus&id=1076 http://www.seriouslyfish.com/profile.php?genus=Periophthalmus&species=barbarus&id=665 http://en.wikipedia.org/wiki/Biological_classification Often Confusing Terms Explained (1.8) Brackish - Slightly salty water. pH - This is the standard way of measuring how acidic or how alkaline a liquid is. The 'neutral' point is 7. Amphibious - Relating to, living in, or suited for both land and water. Substrate - The surface or material on or from which an organism lives, grows, or obtains its nourishment. Thermo-regulation - Thermo-regulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different. LFS – Local Fish Store Food Chain - The transference of energy between life. ie grass photosynthesizes sunlight, cricket eats grass, frog eats cricket, snake eats frog, hawk eats snake. Typically, there is less energy the higher up the food chain, so animals at the top of the food chain have to eat in higher quantity. Salinity - Salinity is saltiness and is measured in parts per thousand or ppt for short. Genera - The plural of genus, A grouping of organisms having common characteristics distinct from those of other such groupings.