A GUIDE TO CARING FOR AROWANA FISHES
silver arowana eating
Probably the most majestic fish within modern day fish keeping aquariums. Named the dragon fish by Chinese aquarists for good reason, its large coloured scales and beautiful movement make it seem like a shiny monster in the water.
This fish has many different variations leading to huge differences is pricing. The Australian version of the Arowana is the Saratoga, both the Jardini and Leichardti are great additions, they uphold the same characteristics as the Arowana’s found overseas, its just they are legal within Australia.
The silver Arowana is by far the most common and popular in the United States due to its cheap price and small starting size. You must not be fooled however, for it can grow up to 2 feet in length and easily break through aquarium glass if it becomes startled or angry.
Green & RTG Arowana
Other variations include the Green Arowana, which is slightly more expensive and then the RTG variety, which are imported from overseas with a microchip.
RTG species are near extinction and so there prices have become astronomical, around $1000-5000 for a single fish. If you are not an experienced hobbyist then don’t even bother. They are the same as any other type of arowana, it is just they are becoming so rare the price and demand has gone through the roof.
Arowana’s will need to be fed a composite diet of both meat and vegetables. If just fed fatty, meaty food’s there will be a build up of fat above its eye, resulting in the unwanted “drop eye” syndrome which substantially decreases its reselling value.
Live foods will be a nice treat for these monsters although it can promote agression. They are best kept with a small school of Arowana’s but of course this is most difficult due to the extremely large tank you would need. Try not to turn your Arowana sour and into a blood thirsty predator by only offering live food as a treat or occaisonal snack.
Crickets and mealworms are great and whats even better is you are able to breed these seperately to have a constant supply of food!
This fish should not be kept with any other smaller fish in the aquarium, it will need to be completely solitary unless with its own kind or other huge fish. Try to keep more than two if you keep a species tank as just having two can become very territorial.
L46 ZEBRA PLECO
The Zebra Plecostomus is a spectacular catfish that is wanted by nearly every fish keeper but unfortunately purchasing it is not always that easy as they demand a high price, much more than the normal rate. This fish is also commonly known as the Zebra Pleco, Imperial pleco or by the L numbers; L46 or L98.
The zebra pleco has bold black lateral stripes running across a white body with a black stripe running over the body from one pectoral fin to the other. The dorsal fin has a high expansion and it is possible to develop a blue twinge when in prime condition. It has a sucker mouth with 4 whiskers. Like other pleco’s it has a flat-ish stomach.
These pleco’s come from the rivers of Rio Xingu, Para and Brazil. They require a pH of 6-7.5 but seem to be doing best in a water pH of 6.5 or just under 7.0. A minimum tank size of 30 U.S gallons (113 litres) is required and a temperature of 78 – 86 °F (26 – 30 °C).
Rocks and decorations should be placed in the aquarium in a way that caves and hiding places are created for them, so that they can take refuge when necessary. It is believed the more hiding places there are the more they will come out into the open, knowing they will be able to hide whenever they want. Fine sand or river gravel should be used for substrate. Rocks should be placed in the aquarium to imitate its natural environment as well as driftwood. A powerful filter is needed as they require a strong current.
They are shy, nocturnal fish, generally coming out at night. Competing for food is not something this fish is good at. If other bottom dwellers are kept along with the zebra pleco, be sure that they aren’t of the aggressive nature, gobbling the food without the zebra pleco getting any of it. It is known for them to be territorial towards their own species as well as a small retreat they may take as their territory, hence the reason caves are needed, especially if more than one zebra pleco is kept in a single aquarium. They grow between 3 – 4 inches (7.5 – 10 cm) and their lifespan is known to be about 10 – 15 years.
When first introduced to the aquarium it is essential to make sure that the zebra pleco is getting food. Due to their shy nature they may be too shy to come out into the open to eat. Feeding them in quiet spots where they don’t feel threatened is advised. As this is an expensive fish, going one step further in its care taking is not a bad idea. Zebra plecos are omnivores. Live and frozen foods, such as blood worms and brine shrimp can be fed, however live foods are more appreciated. Crushed peas with the skin removed, corgette, also known as zucchini or baby marrow are good for the veggies part of the diet. Tetra prima and algae wafers too, can be fed.
To be able to tell their genders, the male has a broader head and the first pectoral fin ray is thicker for the male then the female. Also he has thicker hairs on the pectoral fins, while the female’s is visibly thinner. The females head is also decidedly rounder than the males.
With the temp at 82 °F, the aquarium well aerated and caves or driftwood that resembles a cave, spawning can take place. Spawning takes place in several batches within the cave. The male will at first block the cave entrance with his head. Eventually the female then persuades him away from the entrance of the cave to fertilizes the eggs. The male may even push her out of the cave. 99 % of the time, the first spawning will be a false test with none of the eggs hatching. The male will guard the fertilized eggs and the female won’t even be allowed into the cave. There are usually 7 – 15 eggs laid in each spawning. The eggs take 7 days to hatch and by day 10 of the fry’s life, the yolk sac will be gone. They will take most fry food as soon as the yolk sac is gone. It takes 2.5 months for them to reach 1″ (2.5 cm).
BLACK DIAMOND STINGRAY
Common name: Leopoldi Stingray, Polka Dot Stingray, Black Diamond, P13, P14, P62
Scientific name: Potamotrygon leopoldi
Average Adult Fish Size: 24 inches / 60 cm
Place of Origin: Rio Xingu basin and Rio Fresco in central Brazil.
Typical Tank setup: Filtration is one of the most important aspects of a ray set-up. A large and efficient biological filter is needed to cope with the amounts of biological waste produced by an active, predatory fish of this size. Dim lighting is preferable, although once settled in most rays will also be active under brighter conditions. Plants that require rooting in the substrate will be eaten. Use river sand as this will give a lovely natural look.
Recommended Minimum Aquarium Capacity: 265 gallon / 1000 litre
Compatibility: Rays have to be among the top predators in the habitats they live in nature and are unsafe to keep with most other species. On the contrary they also seem to prefer a quiet life and will often fail to thrive when kept alongside very aggressive or territorial companions. The best tank mates are large enough not to be eaten, peaceful and ideally occupy the upper parts of the tank. Some cichlids, such as Oscars work well. Plenty of enthusiast’s arowanas with their rays, and in a spacious tank this can be a very remarkable combination.
Temperature: 68 – 88 Deg. F / 20 – 29 Deg. C
Water chemistry: pH 6.0 – 7.5
Feeding: Wild rays feed primarily on other fish and invertebrates, including worms and crustaceans. They’re active fish with a high metabolic rate and as such will need feeding at least twice a day. They’re also notoriously big eaters and it’s going to cost you a lot of money to keep even a single ray in good health. In general an exclusively meaty diet is preferable, although some will also learn to accept dried foods.
Sexing: Rays are easy to sex. Males have a pair sexual appendage known as “claspers”, one on each pelvic fin. These are used to inseminate the female when mating and are clearly visible, appearing as finger-like extensions extending backwards from the inside of the fin. In young males they’re much smaller, but can still be seen if you look closely.
Breeding: Rays can be picky when it comes to choosing a mate. Simply buying a pair of rays and putting them together will not guarantee a successful pairing. The ideal way to obtain a pair is to buy a group of juveniles, housing them in a huge tank and allowing them to select their own partners.
The spawning act itself is quite brief, lasting only a few seconds. Fertilisation occurs internally, the male inserting one of his claspers into the cloaca of the female before releasing his milt. Following a successful mating event the male should stop harassing his partner.
In captive rays generally takes between 9-12 weeks. During the latter stages the developing young can sometimes be seen as a visible lump rising from the posterior end of the female’s back, although in well-fed specimens this can be tricky to spot. It’s essential to feed the female in sufficient quantities during this period as she will expend a lot of energy providing for her pups, and her appetite will increase significantly.
The pups usually have a small yolk sac attached at birth, and they will feed from this for anything up to a week. After the sac has been absorbed they should be offered high quality live and frozen foods several times a day.
Additional Information: Leopoldi Stingray is arguably one of the most stunning freshwater species in the hobby and comes with a price tag to match.
Along with sawfish and sharks all rays they have no bones in their body, with the skeletal structures being composed primarily of cartilage.
These fish are dangerous. Most natives of the countries in which they’re found are far more fearful of rays than other supposedly life-threatening species, such as piranha.
The actual stinging apparatus or spine is formed from dentin and possesses associated venom glands.
If you live in a northern climate then chances are good that you see snow and ice as does your koi pond. Its natural to worry about your koi during the winter periods, especially if they have been around for years and years. Fortunately, koi are adapted to dealing with cold temperatures and an iced-over pond. They have a few tricks up their “sleeves” to deal with the inevitability of ice cold water.
Regulating Body Temperature
Thermoregulation of animals or how an animal regulates its body temperature can be a confusing subject. For example, within the subject of thermoregulation there is:
There’s a lot of variations in the world of temperature regulation in animals but to make it more straightforward for koi owners you should know that your fish are ectothermic,which means that their internal body temperature is governed strictly by the ambient temperature (or in this case, the water temperature). So that must mean that all fish are ectotherms, right? Not necessarily. Unfortunately, biology is not always consistent. For example, the bluefin tuna and some sharks create internal heat from muscle activity yet are still largely affected by water temperature which puts them in a category known as mesothermy. Furthermore, the term “cold-blooded” is actually not all that accurate. A “cold-blooded” lizard in the hot desert sun can achieve an internal temperature greater than that of humans. So in everyday conversation its just easier to refer to mammals and birds as endotherms and just about everything else as ectotherms.
Biological Activity and Temperature
You have probably noticed throughout the seasonal changes that as the water temperatures get colder your fish start to become less active. As a result, they require less food and at somewhere between 50 and 40 degrees F they stop eating all together. Ectotherms are able to pull this off because they don’t have to maintain a certain internal temperature and, in fact, they can get away with using as little as 10% of the energy of what a mammal would need. As temperatures fall, the rate of internal biological activity decreases which includes things as basic as how fast a muscle can twitch. This concept in biology is known as the Q-10 coefficient.
Planning for Winter
There’s not much activity going on with your fish, on the inside or outside. They don’t need food and not as much oxygen however its still a good idea to keep some of your pond unfrozen with a de-icer for gas exchange (and some pond owners will run aeration all year long). One of the things your koi will do is try to hang out in the warmest part of the pond and that will subsequently be the deepest part. In general though, its a good idea, when designing/building a koi pond, that you make it at least 3 feet deep to avoid the possibility of total pond freeze. Another thing you may want to keep in mind is that adding salt to your pond before winter will lower the freezing point of water and artificially cause your water to reach a super low temperature which can potentially harm your koi.
Koi in Dormancy
So what exactly are they doing under the ice? Sleeping? Playing cards? As with thermoregulation there are a lot of different ways to go inactive during winter (or periods of less-than-ideal conditions). There is:
hibernation in mammals
brumation in reptiles
diapause in insects and
aestivation in invertebrates
but ultimately your koi under ice are in a state of dormancy. Essentially, they are simply “chilling out” in a state of super decreased activity and metabolism while waiting for spring. Perhaps you don’t get to enjoy your koi as they mill around under the ice but just think of the money you are saving not buying koi food!